How would you do a multi-project chip without something like a "management engine"? By the nature of semiconductor fabrication, you have a bunch of identical chips, but you want each contributor to the chip to be able to use it for testing their own contribution. It seems like that means you need some way to dynamically configure which of the many projects on the chip are actually connected to its I/O pins?

To clarify, since unfortunately griefers are flagging your comment to impede the discussion, so I'm not allowed to reply to it: Tiny Tapeout is a multi-project chip, not a multi-project wafer (though it is one chip in a multi-project wafer). Typical minimum die sizes are 0.8mm², which is about 2 million potential transistors in 130nm processes. That's big enough to put many projects on a chip. That's why Tiny Tapeout cost US$300 while MPW prices start at about US$3000 and more typically US$9999+.