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Sure, so can pypy.

But that means you have to add all sorts of dependency tracking, such that you are able to deoptimise any function affected by mutation on things which were optimised in or out.

This means your complexity increases very fast, very high, before you can have anything which actually works.

If by "just fine" you mean, "with incredible engineering resources funded by a small number of large companies with deep pockets and with some performance cost to check that the optimization is still valid", yes.

It can, but it doesn't have a "do reasonable things" mode. Instead it notices when you do something unreasonable and undoes its optimizations.