I'd say putting the point where Holland became Nouveau Riche around the fall of Antwerp is way too late. In 1441 the Hollanders (without Flemish support, but also without Flemish opposition) had already cracked open the Baltic against Wendish-Hanseatic opposition (being such a mess, most of the Hansa was neutral and some of it supported Holland). In 1411 the Prussians already tried to embargo Holland in Danzig (and failed, though through external interference).
When in 1451-57 the Hansa got into a squabble with Flanders, trade already shifted to Holland, as well - supporting the point that in the mid-15th century Holland was already a key point in trade, rather than the fall of Antwerp being the sudden start.
And the first travels to the East, while no doubt also funded by Antwerpian riches, were not their exclusive domain; the first journey of the 'compagnie van Verre' was funded by a group of men living in Amsterdam, but coming from Kampen, Antwerp, Amsterdamx5, Haarlem, Dranouter (a village in West Flanders), and some I can't find the source for. so 2x Flanders/Antwerp, 6x Holland, 1x other-Dutch. The Brabantsche Compagnie evidently had more southern influence, but still started with Amsterdammers too; the Veersche compagnie was another Antwerp-influenced one, in its case with Zeelandic support.
And of course the publications of secret Portuguese maps was done by a Hollander (van Linschoten), and the de Houtman brothers who had done additional spying were also from Holland (Gouda, in their case).
So to sum back up: Antwerp falling helped a lot, but Holland by itself was already nouveau riche.
Nouveau but not quite yet riche. Granted, there was a longer period of gradual ascent, but Dutch interloping was comparable to English interloping. Leaks in the system, but no transition yet. The fall of Antwerp was key. Up until then, the southern cities were much richer and far more important than the north. It was the fall of Antwerp which killed southern commercial dominance and ensured its firm transition north.
On Van Linschoten & De Houtman, the curious thing is, of course, that this could have also been done by the Hansa. There was a lot of German money invested and involved in the Portuguese trade to Asia. German factors and German crews (notably gunners) were a constant on Portuguese India runs. Any one of them could have sat down and written it up.
What is missing is, of course, is the element of motivation. The Dutch revolt was accompanied by a Spanish blockade that cut the Low Countries from access to the Portuguese spice trade. This was particularly painful for the Antwerper families, who made their fortunes over the previous century in it. They had the money, the distribution networks and the experience in the spice trade. If they are excluded from receiving the Portuguese spice hauls, then they must go to Asia and get it themselves. Petrus Plancius, the major agitator for this, was a Brabantsche refugee.
Do not put too much weight on the names. Adventurer consortiums are always shadowy, their named heads are usually chosen for political connections rather than reflecting actual investment.
How come Antwerp was so rich back then, was it the wool trade or what?
I guess the fall of Antwerp relates to Spanish shenanigans?
Everything converged on Antwerp.
Bruges's outlet to the sea had silted up and a lot of Flemish trade (including the wool trade) had to go through the Scheldt and thus Antwerp. The Bourse at Antwerp was set up c.1460, serving as a permanent "fair" for the cloth industry.
But perhaps more important was the international networks converging there after 1500. Most Portuguese spices from Asia were delivered directly to Flanders, initially Bruges (to be picked up by the Hansa distribution networks and sold across northern Europe). But the silting led the Portuguese to move their depository to Antwerp by the 1510s. They also brought all their West African gold there to swap for German silver, which was carried up to Antwerp by internal river routes (Portuguese needed silver, not gold, for the Asian trade, and Central European silver, dominated by a handful of German families, was one of the world's major sources).
Then came the Spanish - needing gold to pay for the Spanish army in Flanders (they don't take silver), Spanish agents (i.e. Genoese) set up Antwerp as the keystone of Spanish state financial circuit. So Spanish silver coming from America (after touching Seville) would be shipped to Genoa, part of it traded in Piacenza (for Venetian gold from Alexandria), but much of it was carried overland up the "Spanish road" via Besancon to Antwerp, to exchange for the gold running loose there. To soak up the gold and prevent it from leaving Hapsburg dominions, the Genoese in Antwerp organized an elaborate financing circuit system. They used bills of exchange to clear balance of payments between the Low Countries and Italy, and sold Spanish state bonds (juros) in Antwerp, bought locally with gold and re-paid in American silver at a future date. Antwerp was thus the key center in financing the Hapsburg-Spanish empire during the 16th C.
So all the great international streams of wool, cloth, spices, gold and silver converging on to one little town catapulted Antwerp overnight into the world's major commercial & financial center. And once it was there, that's where all great merchants went to strike trade deals with each other, and where everyone who needed financing went - including all the European monarchs. Except the French. French royal agents were naturally excluded from Antwerp, which was a Hapsburg center. France tried to erect a rival system in Lyons, using Florentine agents, hoping to siphon off some of that stream, but it paled by comparison. The English were also almost entirely dependent on Antwerp, despite the efforts to Sir Thomas Gresham to break that dependence by erecting the "Royal Exchange" in London.
So Antwerp ruled the world for much of the 16th Century. It all came crashing down when the Spanish army of Flanders, their pay in arrears, mutinied and went on a violent rampage and sacked Antwerp in 1576. (fault of stupid Spanish nationalists - annoyed at the fat profit margins the Genoese were making, the Cortes of Castile forced the King of Spain to default on Genoese lenders in 1575, prompting the Genoese to suspend their financial circuit, which led directly to the army going unpaid). The army rampage went on for eleven days, destroying a third of the city, driving out streams of refugees.
Although devastating, the sack was not immediately fatal. Philip II backtracked and restored the Genoese. Naturally, all trade was re-routed elsewhere for a while, so the city was unable to recover quickly. Then came the blow of the Spanish trade embargo. Antwerp joined the Union of Utrecht in 1579, and was thus in "rebellion". So when Spain acquired the Portuguese empire in 1580, the spice teat was shut off. The final nail was 1585, when the city was conquered by Alexander Farnese (Duke of Parma). Although the Spanish troops were kept in line this time, Farnese ordered all Protestant residents in Antwerp to wind up their affairs and leave. More than half the city (c.100,000) ended up emigrating north to Holland. Although Antwerp was restored as part of the Hapsburg financial circuit, it was definitely over now.
To ensure it would never revive, the northern Dutch, being such helpful folks, promptly set up a naval blockade of the Scheldt in 1585, preventing trade ships from reaching Antwerp, a blockade which they continuously maintained for the next two centuries (until 1795).
