The aim is to hit and not get hit, but the mechanics of decision-making are a bit more complicated than that. Most broadly, the contest is won by the fighter who wins the most rounds, not the fighter who lands the most punches. Sometimes they'll be one and the same, but not always. A fighter can put on a savage 3-4 rounds where they land 50 more punches than their opponent in each of those rounds, but if they've been slightly but clearly out-boxed in the other 8 rounds then they will (quite rightly) lose the fight, even if they've landed a greater number of punches across the 12 rounds. The trick is to win rounds, not to win the punch count.
Golovkin put together some very strong rounds towards the end of the fight, but it seems to me that he turned up to the fight too late. His strong rounds were brutally impressive, but it was too little and too late, although if he'd pressed his advantage harder in that final round then he would have won the fight.
Yep, realise that, but don't think that was the case here.
Apart from a couple of rounds that I thought Golovkin won quite clearly most of the others were very close, and (just my opinion of course) I thought he landed more scoring punches over those ten rounds, certainly enough to earn him the points.
Close call no doubt, closer then their first encounter where I thought he was robbed blind.
Not sure your last statement is correct, think you'll find that had he won the final round on all the judges cards the best he could have achieved was a draw, would still have been better then a loss though I guess.