"if only we could align the models just a tiny lil bit better" is a rehashed "if only we could escape untrusted inputs just a tiny lil bit better" from 2000s, that were RIPE with various form of malicious injection.

Every command+data channel in existence has been and will continue to be exploited one way or another, because the solution space is for all intents and purposes unbounded. Sure, highly defensive escaping reduces attack surface dramatically, but e.g. prepared statements eliminate the whole class of bugs.

As far as I understand, current LLMs are architecturally incapable of this separation. Given the inherently recursive nature of GenAI, the model itself is part of the input space, making validation essentially impossible.