Right now Ma Long is obviously playing a lot better. Over their careers they have both accomplished amazing things. Would ZJK playing the best he has ever played beat Ma Long right now? Sometimes.
Next Level (I think he was the one, or maybe it was wturber) not too long ago did an interesting simulation of showing how a table tennis match would look if every point was a flip of the coin. One player would probably win in 7 games and in some matches it would sometimes look like the winning player had made a dramatic comeback. That is often how random stochastic processes work. Those two have played a lot of matches that amount to that.
But the 4-0 crushing at Rio seems to reflect the level of their games right now. Ma Long has long ago quashed doubts about his ability to win big matches. And at a technical level his game has no weakness. None.
It was Wturber but I have similarly embraced the role of luck in TT for a while now.
Was it really about winning big matches or was it a Wang Hao problem? Yes, Ma Long was a bit of a wreck about losing but I think that Wang Hao was the more the issue than the size of the occasion.