One obvious difference is that 2FA prevents the attacker from taking ownership of the package and distributing a malicious version, vet theoretically prevents installation of the malicious version. The vet approach comes into play much later.
Also, as I mentioned before, there's no evidence whatsoever that the 'vet' approach even works, let alone scales.
I didn't say they're the same, or even practically equally effective at all cases, I said one is a superset of the other's threat model.
2FA covers cases where the attacker is not supposed to be authorized to distribute the package. But vet covers all cases where the code isn't doing what it's supposed to do; that includes cases where the attacker wasn't authorized to distribute it, but also cases where the attacker was correctly authorized, or the authorized person simply made a mistake.
An actual disjoint model is something like Go's TOFU proxy, which makes no claims about who was authorized to do what or what the code should be doing, only that it's the same for everyone.
vet aims to reduce the volume of attacker controlled code and accidentally dangerous code after release.
they operate on distinctly different timelines, against different threat models, with different actors.