>>58072406
>Why did Megaevolution succeed where other gimmicks didn't?
It was the first one.
No really. That’s it.
Design wise, Tera is more mechanically interesting, and Gigantamax is easily better visually.
But Mega was flashy and new. Z-Moves were obviously never going to be as big of as transforming your whole mon, and by the time we got to Dynamax, everyone was already sick of gimmicks.