Fellas I'm gonna be real: if a singles tournament ever exists its gonna be a bss 3v3 one. 6v6 is too much of a slog.
Gonna say this before we move back on topic but: you can compare pokemons balance with tcgs, which are known for being extremely hard to balance. There's a lot of moving parts, new expansions, the innevitability of powercreep etc. Bear in mind card games only need some % of cards to have casual appeal, as the rest either dont need it or can be made for competition only, while pokemon needs a large % of mons to appeal to casual gameplay, otherwise teambuilding feels punishing and unfun.
what gamefreak does is that while theyve embraced powercreep, they seem to try and tailor the metagame around the powercreep, which may leave a lot of pokemon behind but still makes for a good format. Doubles also help powercreep climb slower.
Of course, this means that singles 6v6 was left in the dust, but I dont think gamefreak ever saw this as a highly competitive format, but a casual one