This would be what's known as software-based fault isolation, right? Here's a paper from 1993: https://dl.acm.org/doi/abs/10.1145/168619.168635

I don't understand why this idea keeps failing to take hold even though it's constantly reintroduced in various forms. Surely now, 30 years after that paper was published, we can bear the "slightly increased execution time for distrusted modules" in return for (as the paper suggests) faster communication between isolated modules?