About how many planets/metallurgists is that?
From my inward perfection + agrarian idyll game at year 2415: 30 systems, 9 planets out of 17 total have alloy buildings, with a total of 30 tier 3 alloy foundries. That adds up to 240 metallurgist jobs spread across those 9 planets. No special species traits that boost specialist production, so all bonuses come from stability, the militarized economy policy, traditions (all are unlocked), and production ministry buildings. 990 alloys produced per month, with 330 alloys taken up by ship maintenance for a net surplus of 660 per month.
I could have invested higher, but at this point I don't need to. My fleet cap is 800 and I am 400 fleet power over the cap. I can spam a full 200 FP battleship fleet and recover the alloys fast enough such that when the fleet is completed, I can make another. I may have to build more alloy foundries when one of the FEs awaken or the end game crisis appears.
The matter decompressor is the only reason I can support that level of alloy production. If I didn't have a black hole in my territory, I would not have been able to sustain that rate of production. I don't have a lot of natural volatile mote deposits, so I am relying heavily on chemical plants on my 2 habitats to maintain the alloy foundries.
I'm at 400 Alloys in 2330. Only thing limiting me right now are minerals, but the matter decompressor is already under construction.
I ramped up my alloy production in the last decades. The first 100 years were a build up for that
I agree, it takes some planning now to make the jump to mass production of alloys. Was your experience any different from what I described above?