2010 - so the Thunder were suppose to win a championship with dudes that were barely out of college?
2011 - same applies as above
2012: They went to the Finals with a bunch of dudes who were in the mid-20s, that's a feat in itself. Playing against arguably the best SG, SF, PF in the league.
2014: Was Ibaka not injured for two games of that SA series? They weren't healthy.
So yeah your argument is leaking. Since their finals defeat, the Thunder haven't been healthy to the point we can say "OKC couldnt win when they were healthy".