If your true Elo is X, then you'll be able to manage an exceptionally high win rate at X-i for as long as i remains a significantly high number.
However, with each win, i gets small, and as i approaches 0, your win-rate should also approach 50%.
You're not going to simply manage a 75% win rate all the way up until you finally hit your Elo. It's not that black and white. A more realistic example would be starting at an extremely high win rate (say 95%) and that win rate steadily declines to 50% as i approaches 0.
So perhaps if your true Elo is 2400, you manage 95% at every Elo below 1000,
90% win rate from 1000-1499
80% win rate from 1500-1699
70% win rate from 1700-1899
60% win rate from 1900-1999
55% win rate from 2000-2099
52% win rate from 2100-2399
and then a 50% win rate at your true Elo 2400+.
Now, this is just a made up example, but the model helps to illustrate the point I'm trying to make.
The closer you are to the Elo you belong, the closer you are to being at an Elo with other players of your skill level, and therefore your win rate will begin approaching 50%.
But it won't hit 50%, not if you're still truly below your appropriate Elo.