How long do you think it takes for those factories to go from nothing to making state-of-the-art chips at a scale that's large enough to influence the supply even by 1%?

There are plenty of them being built, yes. Some of them will even start outputting products soon enough. None of them are gonna start outputting products at a scale large enough to matter any time soon. Certainly not before 2030, and a lot of things can change until then which might make the companies abandon their efforts all together or downscale their investments to the point where that due date gets pushed back much further.

That's not even discussing how easier it is for an already-established player to scale up their supply versus a brand-new competitor to go from zero to one.