Bill Zebub
“It’s probably Matt Mercer’s fault.”
I can only speak for myself (naturally!), but I read a comment on Reddit a few years back that summarized my feelings about OSR vs 5e (for example): "what was once narrative is now mechanical." In other words, having been playing these game for a very long time, I prefer a lighter rules system because it encourages player creativity vs. depending on whatever mechanics they have available to them on their character sheets. If you want to be a pirate, be a pirate, instead of making your Pirate Check. I also don't like the power gaming: characters are too powerful too quickly. 5e can feel like a superhero game.
Again, one person's opinion.
Yeah, this is pretty much my answer, too.
The specific features I like, such as fewer character options, lightweight or non-existent skill systems, etc., are all just manifestations of that philosophy.

