If I answer the question, will you?
I think in 2016, the Rams and Fisher were even more of a mess than usual. I think a talented, HOF QB that was already experienced would have made a positive impact on that team though and may have even performed well. Probably not, but possibly. Your example isn't one I'd use to illustrate that possibility though. Aikman was WAY overrated and proved unable to carry a bad offense, especially one not carried by a HOF O-line and running game.
If you're asking if I agree that every QB would have struggled for that team then no, I don't agree with that. Even Foles played well at times but he wasn't exactly an established QB at a good place in his career at the time. But that's a big part of the problem with Fisher. I think he picked his QB's like he picked his OC's. No way would Dan Marino or Jim Kelly or any true leader go into that hot mess and let it remain a mess. But if Fisher thought there was any chance of infringement on his Grand Poobah status, I think he chose not to bring that person into the equation.
So, how would you describe Goff after 2016? Are you arguing that he was considered a blue-chip, starting caliber QB at that point?
Would you take Goff or McVay if you had to make a choice?