This is the main reason I fucking hate megas
Great designs locked to specific games every 12 years
Fucking asinine. If Game Freak wasn't run by retards they would change the lore for all Megas going forward. Something simple as "Some Pokemon grow powerful enough to naturally evolve into the forms previously requiring Mega Stones" This makes them simple evolutions that can appear in every game. Just scale the stats down since they will then be normal Pokemon that can hold items
And just edit Eviolite so that it doesn't affect the 50 or so mons that evolve into former Megas. It's not fucking rocket science