It's necessarily an interactive process. They will want an NDA (you generally can't get the fab "library" or even process information without this!). They'll want to do sales work on you. There's enough bits where they will want to check your work and understanding because it reflects badly on _them_ if the result doesn't work in a way which could be deemed their fault. A lot of this stuff already exists for PCB manufacturers and has very gradually been automated into a SaaS, but chip shuttle is a much smaller market than PCBs and will remain that way.

An example list of steps: https://www.usjpc.com/en/ourbusiness/shuttle.php

https://tinytapeout.com/ <-- there is this project ...

About as soon as a SaaS self-service to order a piloted jet plane.

Either you're really big and can put serious resources into R&D and production, or you can have a few toy-sized offerings for the lowest end that are only good for highly custom or testing purposes, or you are too small to care.

a couple reasons why this is unlikely anytime soon. one is that the engineering processes between the designer and the fab are still too tightly coupled. some for good reason and some that they want to sell you engineering servives.

the other is that the fab schedule is heavily laced with sales politics. getting a timely slot is largely a factor of how important a customer you are and none about scheduling work. they have as much work as they could ever want.