If we had gone down the path of Smalltalk rather than the UNIX-like path we have taken, I imagine we'd see systems with asynchronous message-passing semantics u

If we had gone down the path of Smalltalk rather than the UNIX-like path we have taken, I imagine we'd see systems with asynchronous message-passing semantics using processes/threads. Think something like E (or now Spritely Goblins, which takes inspiration from it) with at least one separate vat per "application". This would result in a system like Smalltalk, but with concurrency to prevent the situation you're describing. I think we'd be in a much better place today had we taken that path, for a number of reasons.