No.
Winning 73 games isn't why Curry is less than 100%. Curry didn't turn his ankle or sprain his MCL slipping on a wet spot because they won 73 games. They have a few guys dinged.
Having said that, its not why they are losing. OKC is playing like the superior team, and hard to say they aren't. Dubs fan for 45+ years, but I'd like to think I'm an impartial fan of the game. They are outplaying Golden St in every category, including effort which is inexcusable.