CGI is making their attempts slicker, but Hollywood is constantly derailed in it’s efforts by it’s own self.

This one was easily debunked by conservative conspiracy experts and widely panned as an example of Hollywoods ineptitude.
Clearly Reagan would not have been pumping his own gas, not in a tuxedo anyway. Fake.

This attempt, Hollywood brought in an actor that resembled a younger Reagan to make a documentary about his years before politics not long after marrying Nancy.
According to conservative critics of the documentary, not once in the entire film did this person, clearly an actor, ever don a cowboy hat.
Fake.
Then there is Bush…
They’ve had a lot more success there. Bush Sr. has been dead for almost 2 years now, conservatives know it, but Robin Williams refuses to break character, so nothing can be proven conclusively.