Unlikely to happen any time soon. The problem is mask manufacturing costs: you spend a lot to make a set of masks, but after that making the chips is incredibly cheap. Great for mass production, not so great for prototyping. And there's a lot of proprietary 3rd-party IP involved in chip production: fabs are not very eager to make that publicly available. Heck, even FPGAs are still mostly proprietary!

That doesn't mean it is completely impossible, though. Fab2 (formerly Atomic Semi, of Jim Keller and Sam Zeloof fame) is trying to do exactly this by aiming at making small-scale production affordable. The trick is to replace the whole mask-based lithography with electron beam scanning: way slower, but no mask costs.

But they are now targeting selling mini-fabs to R&D labs rather than offering an affordable ASIC-as-a-Service. Let's hope one of their customers makes it available to the public!

We’re at approximately where PCB pricing was 20 years ago, which _is_ a big deal: https://wafer.space