There is actually a really cool history of color grading and the advancement of computers in film technology. The movie O Brother Where Art Thou was the first movie to use full color correction, that was only possible with newer computer assisted editing, and lead to a Oscar award as well as future technical awards for its impact on film editing. Before that movie, color grading was seen as a last ditch effort to compensate for failings of a lighting director or poor cinematographer and was expensively and painstakingly done on select frames individually, and never done on more than a scene or two. After computers were used for digital editing and made it cheap, fast, and easy (relatively), it has become the standard. And now with digital cameras, it is literally baked into the process. It's a really fun rabbit hole to go down, would recommend.

The snow should be all gone from the mountains in the second pic

Indie movies are better about this.

Obsession, I Saw The TV Glow, and Titane are all much more color vivid

In the 00s everything was brown.

Part of it is the studio doesn't work as hard on scene color and lighting and shading because of the assumption it can all be done in post.

Colour grading like this has less artifacting on streaming services is the primary reason i think

You forgot about the 2010 years, where color was completely overblown and even the dirty dishes were almost glowing.

This is a weird observation to me. I've been watching a lot of documentaries recently. The color and image quality is orders of magnitude better than ten years in the past. Sometimes they actually oversaturate to the point it's hard not to be put off by it. Is OP watching crime movies and expecting Planet Earth visuals?

4:3 vs 8:5