No way. It is not sampling bias. Big budget movies have gotten worse script wise compared to the 90s and 00s.

The scene workers have gotten better though. And there are a lot of good movies being made still, but not by the mainstream industry that used to really deliver.

If that was the only reason I could name a dozen watchable movies from the last decade, but I can't. I can name a dozen good movies from 1984:

1. Beverly Hills Cop

2. Ghostbusters

3. The Terminator

4. Gremlins

5. A Nightmare on Elm Street

6. Police Academy

7. Dune

8. Repo Man

9. The NeverEnding Story

10. Karate Kid

11. Romancing the Stone

12. Indiana Jones and the Temple of Doom

Or pretty much any year from the 1980s and 1990s.