With enough money and training/rallies everybody can get to a certain level. But those last 1 or 2 percentages are the most difficult to find.
For sure Rovanpera has talent, no doubt about it. But people are blinded by his age, which means nothing. It's experience that counts.
We have seen a lot of young guys in the past, storming trough cups, JWRC and even wrc2 but never got to a decent WRC level.
So, he has to prove in the next year(s) he has what it takes to get to WRC level.
I'm not saying he is not going to make it, but imo it's still too early to tell