I think that's important to be said here. I get why they took him. They don't think they'll be selecting high in 2026's draft, and Simpson is a player with excellent mechanics and a nice arm who can execute McVay's scheme. They rolled the dice on him.
From here all that matters is whether he can live up to expectations. But just remember this is a coach who threw Goff out. McVay undoubtedly has the highest standards with QB of any coach in this league.
Do they see him as a QB2? Quite possibly. Would they use the 13th pick on that? I would normally say no, however to have a young option who may be good enough to plug in to this offense is definitely preferred to enduring Jimmy Garoppolo throwing 50 screens and pop passes. So I'd have to say it is possible you are right, that him serving as a backup may be enough in the Rams minds. Not that they would admit that. And he does have a chance to hit. So I am all-in rooting for this kid even if I don't think he's gonna be good enough.