Honestly, at this point with the state of the film industry, I'd be OK with a type of a Hayes code. When was the last time we've had a Casablanca, Citizen Kane, Gone With the Wind, North by Northwest, Lawrence of Arabia, All About Eve, Sunset Blvd, and on and on and on...
We need a CGI, percent of films that can be Marvel junk, percent of films that are actually decent grown up-geared storytelling, and on and on.
There have been many MANY great films and in looking at my 2010s list, we've had some of the best films of all time pop up in the past decade or so, BUT these are mostly all indie stuff and they don't play at multiplexes.
But again... tariffs ARE NOT the answer to the crisis the American film industry is currently in.
This line of thinking assumes that 1) the enforcement of the Hays Code was responsible in some way for those films you mention being "great", and 2) that time won't be as kind with more recent films as it has been to some of those you mention. I mean, even
Citizen Kane wasn't heralded as the masterpiece it is today back then.
The other thing is that you argue about the poor state Hollywood is in now and how "some of the best films" from the past decade are "mostly all indie stuff" only to look back at a time and conditions when studios pretty much had a chokehold on the film industry.
This is one of those things were every generation just thinks that the past times were better, that the glory days are gone, and the system is beyond repair. I'm sure that people in the 60s, the 40s, the 20s, all complained about the same. Anyway, there will always be great films, there will always be crap films, and there will always be mediocre films that people will forget 4, 10, 20 years after.