Yeah it doesn't matter if you have the best hardware on the market, if you don't have the games to back it up, you'll struggle to sell.
Xbox Series has basically stalled in sales and is too far gone to salvage at this point, but Nintendo has proven multiple times that a generational reset can reverse a brand's fortunes. But that can only happen if they fix the underlying issues, like Switch did.
If they got into Xbox 5 with the same lacklustre first party output, it will flop.