Yes, it's very evenly matched for elite players:
https://twitter.com/S2LSOFTENER/status/950091737212641281
Sure, I think it is that easy to make the all clear setup. At my local gaming center I had everyone Perfect Clearing within 10 minutes. You make the memorization sound a lot more difficult than it really is. All I had to do was show them the Perfect Clear lead-in form and tell them to "mash rotates to get the next 3 pieces to fill in the hole somehow" and they did it lol.
Personally, I think it's a bit misleading to call any Tetris setup "hard"… With the
7-piece single bag randomizer in play, the build method for any Tetris setup has been "solved". This makes defining skill levels in Tetris difficult because pretty much anyone can make the most common setups in Tetris with a little bit of research. Once you train your mind to see those options, the only real limiting factor left is the ability to go fast.
On the other hand, Puyo is much more difficult than you're understanding. Have you actually tried those "simple" puyo patterns that generate "regular" 5-7 chains? There isn't a clear-cut way to make them the same way over and over since Puyo Puyo doesn't have a predictable randomizer like Tetris.
As for determining whether Puyo chaining or Tetris setups "demand more" from a player... well, that's subjective. However, you can determine for yourself whether playing Puyo is really easier when you see what players have to go through to reach the highest levels of play.
https://twitter.com/rockraining/status/869709817887240194
https://www.youtube.com/watch?v=QVORkRFZt3I