Another debated detail is that the aforementioned Szapolyai, who - among other titles - was the voivode of Erdély and was responsible to gather the troops from there, couldn't make it in time to the king's camp. The notion was put forward he did not so on purpose because he could profit from the death of the king etc, then it was refuted, the troops come to his flag too slow, got contradictory orders from the king, etc.
As for the reality of the battle, the Ottos were at their peak, while Hungary in itself compared was just not enough. Even if we won that battle (wasn't impossible entirely, and Szapolyai's army could have made the difference) it's questionable if we could the next one or the one after that, the war was essentially lost on the long run. Turning it over would have needed a closer cooperation from the powers (Austria, Czechia, Polan, Hungary) in the region, and that wasn't able to happen in the previous ~150 years, the chance was pretty slim for happening then as well.
Frankly the morale of the story is what I already mentioned a couple of times, without the mutual support of the countries around here, we all be just the bitch of whoever comes from the West, the East, or the South. Rarely anyone - if anyone at all - says this.