OP has noticed a real change.
Those that use things like Deadwood and The Wire don't disprove the point. Both of those shows used swearing as a critical part of story telling and scene setting. Fuck, The Wire had the legendary "Fuck" scene
I've noticed it in more modern shows and it feels cheap and lazy, added in to be edgy, I dunno, but it's rarely artistic in approach and entertainment is supposed to be art and make a statement.
The tired line is to say it's part of the Millennial style, which is a bit diluted, but is a thing for a reason.
I've worked on franchise entertainment productions that have crossed through this barrier and I've seen the direction mandates literally state "We want to change the tone to be more light hearted, and Marvel like in approach, and not linger on dark parts too much by bringing levity and lighter quips". So it's no surprise that people have noticed and seen it become a thing.