That's the mindblowing thing in all of this. In Mexico? Dudes game was LOCK TIGHT. Like, after seeing the hype around him for a while. I started checking his stuff, and was fukking blown away about how this dude was doing some next level spots and pulling them all off seamlessly. He was shytting on every high-flying wrestler in the world, and making it look easy. I can understand entirely why the deal was made to bring him in, as Mistico just instantly hitting like Rey in '96 seemed the safest, easy conclusion to reach. Ever.
And as you said, it's not like he was forced to work a different style and his matches were just not great. Dude was just out there blowing everything.
It HAD/HAS to be mental. Has to be. If you watch his shyt from CMLL, you won't believe it's the same guy who showed up in America.
That's the single weirdest thing about Cara failing in WWE without a doubt. Not only was he one of, if not
the, best high-flyer in the world in the mid-2000s, but he was also a GIGANTIC draw in Mexico (dude legit outdrew Cena in 2007, I believe).
While I do think that never working the American/WWE style and not really having anyone who knew his style around had a lot to do with him bombing (remember that Mysterio had a cadre of luchadors and wrestlers with experience in Mexico to work with in WCW), he shouldn't have been such a bomb throughout his tenure. Its not like he eventually couldn't have been anything in the future either. I've seen him work in person, and his match (granted, he was working with Cesaro) was over and well-worked throughout. Injuries and whatever the hell affected him mentally in WWE probably did a lot more to tank him than him flat-out sucking (which wasn't really ever the case).
Who knows, though? At least it's over now. Mistico/Sin Cara/Whatever can go back to Mexico and (hopefully) go back to not being a mediocrity, and WWE can just move on altogether.