Ask HN: Why MIT-Scheme is regressing?

mit-scheme is the iconic implementation, the one used by Gerald Sussman, author of the famous SICP textbook. So it's surprising that mit-scheme is regressing, that it's only available for two platforms, that it doesn't work at all on the new Apple M1 processor, that it doesn't work on Windows (although it did before), that it doesn't work on Raspberry PI.

The editor edwin, which is part of the mit-scheme, and which allows beautiful debugging in almost the same way as in SLIME for Common Lisp is documented almost nowhere. If you want to make some new extension or modification for edwin or you want to configure it a little differently, the only way to do that is to study the source code.

I don't know about you, but this is strange to me: it is one of the best (and oldest) scheme implementations, but day by day it is more and more clear that it is slowly sinking into oblivion. Why is it like that?