Yeah, I have seen people mention an FPGA implementation of PICO-8 in the context of MiSTer FPGA as well as Analogue Pocket in quite a few places already. That could definitely bring the project closer to real hardware (instant boot, low audio/controller latency, direct hardware interactions). Also, there are devs who suggest that it may actually be possible with the right approach, for instance: https://twitter.com/ferreira_hugo/status/1305284124488486917
A baremetal (no OS) version of PICO-8 for Raspberry Pi and stronger microcontrollers would have been awesome too. If lexaloffle started brainstorming regarding FPGA/baremetal PICO-8 (on Twitter, for instance), I think we might get some interesting answers/ideas.