Cutting the Dex was the only way to stop powercreep cuz of their need to make the new Gen Pokemon comparable/stronger than the previous gens so people play with them. So instead of having to make a bunch of Gen 8 mons comparable to the Tapus, Genies and UBs, they just cut them out and now everyone is playing without legendaries and the only non legendary with over 550 BST is the Psuedo.