Subject: Re: Sgt Pepper
Was he, though? He was a "crooner", yes? Pleasant voice, but was he groundbreaking?

Yes. He invented crooning as a pop music vocal style. He was the groundbreaker, which is why he was a massive phenomenon. Like any pioneer, once the innovation gets copied by everyone, later folks might wonder what the big deal is. To quote more from the Seinfeld isn't Funny trope:

It wasn't old or overdone when they did it. In fact, it wasn't done at all: this work was the first one to do that. But the result was so brilliant and popular, it became woven into the fabric of the genre. Its innovations were endlessly repeated, until the audience began to expect that every work of that type would include them. And so a work which was once genuinely novel has become the new status quo. It's basically the inverse of a Grandfather Clause taken to a trope level: some works can get away with a dated element because of age and tradition, but these works are dismissed as dated because they've drowned in the sea of their own imitators. The work has retroactively become a Cliché Storm.

There may be a good reason for this. Whoever does something first isn't likely to do it best, simply because those who follow after have the benefits of time and experience. So it shouldn't be surprising that viewers who see the new idea after other hands have shaped and polished it are not going to be impressed by the way it looked when it first came out of the ground.

https://tvtropes.org/pmwiki/pm...

To put it another way, he's literally the source of not just "crooning," but the entire practice of intimate vocals (rather that belting or shouting), in recorded music. But seventy or eighty years later, that's just the status quo, so it seems utterly unremarkable.