I definitely think it's both. There's so much less to practice in smash 4 that you become adept in all the major aspects quicker. Fine-tuning ends up being more difficult, but by the time you're in the fine-tuning stage, I think someone is already good.

Characters are going to generally use the same zoning tools to the same starters at all time, and keep doing it until it works, in Smash 4, at least when compared to Brawl or etc. Think about Luigi -- fireball and grab is basically all he's gonna go for, always, until he goes for a movement read for kill move as a finisher (if he doesn't combo into a finisher). In Brawl, you'd have to mix it up way more (save for very centralized or broken strategies like infinites) because nothing truly worked like things work in Smash 4 -- the neutral was forcibly dragged out, and simply landing a forward tilt mattered so much, that Brawl's neutral had to be far more varied. Granted, a lot of matchups in smash 4 are super varied as well, but there's far too much of "I can just pick Ness/Luigi/Diddy and do Ness/Luigi/Diddy" things. People who struggle don't necessarily have gameplan problems, but they're not precise or fine-tuned enough to compete with the highest tiers of players.

Why would you interpret my comment as saying that I'm "really good" at smash 4 or could compete with Vinnie? These criticisms of smash 4 I've illustrated led to my decision to not pay $500 to play the game, and consequentially, not play it seriously.

I'll generally see something new any time I watch a high level smash 4 game, but I'll see way more of "something new" any time I watch high level Melee/P:M/Brawl. Smash is a platform fighter, make it very dynamic in nature, but as a Smash game, Smash 4 is very disappointing and easy.