Alright, I've played some games with different countries now, and I've been able to win. Here are my economic observations. Naselus, tell me if my thoughts match your data.
1) Industrializing early is pointless until you hit certain milestones. It's not just that artisans start out more efficient, it's that there simply isn't enough "stuff" on the WM to reliably fuel mass production. Trying to industrialize early as Prussia-Germany saw my factories starving for critical resources half the time, even when it was something like coal, which I made myself. Between POPs and RGO inefficiency, there wasn't enough coal to keep cement factories running at full speed every day. So, the lesson there is to only start building up industries when you achieve two things: excess resources relevant to the industry, and excess labor to run it. If your RGOs are selling all of their products, there's not enough excess labor to fuel industrial growth. If there aren't any excess resources, the factories starve half the time.
2) NFing craftsmen is for suckers the first 50-60 years of the game. Because resources are much more scarce, it's a really bad idea to pull POPs from RGOs while those RGOs are selling 100% of their units. If the RGO isn't selling 100% of its units, it starts firing POPs, who will naturally demote to craftsmen, anyway. Instead of NFing craftsmen, you should be letting industrial and commercial techs increase RGO efficiencies to allow for naturally firing POPs from the RGOs. As Japan, Russia, and Germany all could tell you in my games, pulling POPs, via NFs, out of coal mines to work in steel mills only means that those steel mills starve for coal. Starving for resources = bad.
3) The early game is not the time to spam factories. The early game is the time to raise literacy and fund imperialism. All that money you spend building factories that spend half the month starving for inputs could be better spent on building bigger armies that can be used to carve a colonial empire for yourself. Preferably, you should be carving out an empire that provides current or future resources you will need. (I can consume 100% of the world's rubber in 1910, so thinking ahead is important.)
4) Certain resources are so critical that they determine the fate of nations now. Dye is controlled by the UK and Netherlands until Synthetic Dye is invented, so you are at their mercy if you want to produce cloth. Coal is used in so many industries, not to mention POPs using it up, that if you don't have your own coal, you are at a serious disadvantage to everyone else. Iron is really important in the early and middle game. Timber is useful early on, but once Russia gets some techs, it gets much more common. Sulfur is vital to anyone who wants to produce weapons. If you cannot sphere or annex these critical resources, you are doomed to be an agrarian power until you gain enough prestige to buy them or other nations finally produce enough.
5) You should guide industrial development during the first half of the game using available resources. Let the artisans satisfy demand in other products, but let your factories only work along supply chains you have full access to. During the second half of the game, you can start looking at demand more often, but even then you still need to monitor supply. The specter of supply chain problems never disappears completely.
6) Subsidizing industries must be carefully considered. Industries that just keep failing every day of their life should be deleted or closed. The only time subsidizing is important is when you have a sine-wave supply bottleneck or when you need to immobilize labor in a state while you build new factories. That sine-wave bottleneck is a real problem, since the factory gets its inputs half the time, but half the time it's missing something. Rather than just close it down or let it fire workers, I can run that factory at 100% the moment it gets inputs again. Still, letting workers move to industries that are doing better is usually the best strategy.
7) Commercial techs are absolutely critical, now. It's not just input/output efficiency, either. Because there is so little excess money available, using administrative techs to increase admin efficiency can save you thousands of pounds a day if you are a major military power. The tax techs help you raise needed money in the first place (so long as you don't kill your POPs). And the first two market structure techs increase RGO efficiency, which helps for all of the reasons I mention above.
8) Bankruptcies seem to be coming from two sources. The first source are minor powers that enter debt spirals due to unforeseen costs (wars, sudden price increases, tariffs dying). The second source involves major powers that go bankrupt due to lack of available credit. Not only me sometimes, but almost every single GP in various games have gone bankrupt. The problem isn't the interest payments. I went bankrupt on $200,000 in debt (the interest payments did not even exceed my gold income). The problem is that the national banks just don't have enough capital to lend. An analysis of banks in various games has indicated that the general tighter economy in AHD means that aristocrats are no longer cash cows for taxes or lending. As Russia, even putting rich taxes at zero and putting tariffs at zero, I saw 80% or so of my aristocrats not able to afford half their luxury goods. The good news is that their money is circulating in the economy and buying up the products I produce. The bad news is that the Russian national bank has about $400,000 in total assets in 1915, half of which is loaned to other GPs who are also facing similar credit crunches. (Watching France default on 100,000 in Russian debt was hilarious until I realized that I couldn't borrow that money to help finance a war against the UK.)
9) Dreadnought spam is still possible, but only if you are willing to really impoverish your people to do it. If you close the loop and produce all the goods for dreadnoughts yourself, you can sustain their production fairly well. But you have to raise taxes really high, which kills the standard of living of your POPs, which carries with it other consequences. It also means you must research all tax techs to get enough efficiency to draw the required revenue out of your POPs in the first place. And since oil and fuel are finite, there is a point where you can't build or support any more dreadnoughts because there is not enough crude oil on the planet to satisfy your demand.
10) Wars are expensive, but losing access to needed resources is even worse. Also, losing prestige is bad.
11) Prestige is absolutely critical now. The difference between being #2, #7, and #29 is vast. If you can get and keep #1, you are well on your way to building an awesome economy.