Gobert is already insanely good, the only thing is that the sample size is so small. But even without developping any further and just playing like he did after the AS break (11 / 13.5 / 2.6 playing 34.4 minutes a game and those 40.4 opposing paint FG%) he is already a defensive juggernaut by this league's standard and a perennial DPOY candidate (and several times winner).
What is crazy is that right now the key isn't how much he improves, this would be bonus, the key is that he stays that good for a long time. Just the numbers he put up in those 30 games have only been put up in 13 seasons total since 1973 : Kareem did it 3 times, O'Neal and Olajuwon 2 times and Mutombo adn Howard only once ia.
Just playing like those 30 games is already historically good. If those could be his career average for the next say 6 years for example where we account for some form of earlyish decline due to his massive size leading to injuries and wear, he would already classify as one of the most dominant defensive centers of all time in his prime. If he could have similar stats for 10ish years, he would probably start being in the conversation for best defensive center ever.
I mean Gobert has been historically good already.
But just for 30 games.
If he can do what he did for 400, 500, 600 or more games, than yes he is a monster.