This is nonsense.
Goffin was 6 months short of his 22nd birthday when he finally broke into the top 100. You make it sound like he was locked in a cellar all those years but it was his own fault he wasn't good enough to play on the ATP tour until last year.
Lets say you're right. The question is still what would it be reasonable to expect from this point onwards
. Goffin can't go back in a time machine and make different decisions.
Lets say hypothetically, he's turned some sort of corner and is now on the way to being a top player. Is all that potential going to be realized instantaneously? Or does it take time to adjust to a new level of play?