Weird argument that communism is a bad tech, as banking is a worse tech to self-research
At least if you beeline communism you get a GSPY and first dibs at kremlin if you go that route. (Although kremlin is oddly placed here as you probably wouldn't build it if you're going workshops).
In the normal domination scheme you lib, you go nationalism, and then military tradition (for cuirs). Workshops can do plenty well here, as they are already worthwhile and then immediately after MT you tech chemistry.
At no point does it make sense to self research banking, so you're only getting mercantilism once you can trade for banking (which will vary obviously). My point is it's not as much earlier than SP as it may appear, because despite its physical location on the tech tree there's more important things to beeline (namely liberalism and MT).
So when we assume that mercantilism is coming AFTER lib, it means GP have started to dramatically lose their effectiveness, as the trifecta of them being more expensive, Golden Ages taking more and more GP to work, and bulbing researches a smaller percentage of a tech.
And +3 research (or w.e) isn't that good by itself. If you have rep then it's obviously double that. But you get rep two ways, either mids or constitution. If you're in total war mode or about to be constitution is a bizarre detour and the mids can also unlock police state.
Is it better than decentralization? sure, but it may not always be worth the revolt turn, so you have to spiritual / grab it in a GA.
I do run mercantilism a decent amount, probably more than FM as I already claimed ^^
But does it compete with SP once SP is available? Absooooolutely not. At that point GP and research in general mean almost nothing, so the +10% hammer production should be more important than mercantilism by itself. And if you're on a high level and going for a dom victory the high maintenance from all the cities is usually cost prohibitive by itself to make it not a choice.
It's almost an after thought that it makes workshops OP at that point as well.
Also blitz did you seriously do a 360 flip just because elite said I was a deity player
FM may be better than SP in a space race. It's definitely closer, and probably situational. Although I'm not really an expert on space races, since domination is easier. The only time I space race now is with an internet gimmick, where usually workshops end up being more useful for me.