Does this mean computer boards will someday have one or more slots for an AI chip? Or peripheral devices containing AI models, which can be plugged into computer's high speed port?

It doesn't even need to be high speed. A minimal chip would have four pins: VCC, GND, TX, and RX. Even one-dollar microcontrollers can handle megabit-speed serial connections, which is fast enough for LLM communication.

Probably more like either USB sidecar or PCIe drop in. I dont think theyll return to a world dedicated coprocessors.

Unless someone finds a way to turn these thijgs into a bios module.