What I said was conditioned on player sticking to few opening that s/he knows very well. It not hard to convert the advantage to a win, and it's also not obvious that some move is a blunder until after it becomes obvious.
1700 rating is not very clearly defined since different Chess websites uses different ranking system and the rating can vary dramatically. For example, on average there are 400 points difference between chess.com and lichess.com ranking.