Earlier quoted context omitted.
It's not just random vs random. Two extremely weak players will take hours to finish a won game, because the player with the major material advantage does not know how to win! When teaching kids, it's not uncommon to, after teaching them how to move all the pieces, spend time teaching them how to perform the most basic of mates: KQ vs K, KRR vs K, KR vs K. Only after those three are mastered we have a good opportunit…
I still don't know how to checkmate with two bishops. I mean, I've read how to do it, but if you stuck me in an endgame situation, I'd probably draw. Luckily, I have never actually had an endgame with a king and two bishops versus a king. Same thing with king, knight, and bishop.
What I don't want to find is queen vs. rook. I played once queen and pawn vs. rook and won, but it was painful. It seems there are some masters that are specialists in drawing in this positions, even if it should always be a win. Computers with end tables have not this problem.