I mean some of you can stay salty as claim he's not been performing at a great or WC level since the last couple of seasons and that he hasn't become Spain's go to nidfielder along with Isco, but that doesn't change that fact.
As for Roberto then had he not managed to transition into a RB he wouldn't have been at Barça. He almost left before Lucho convinced him to give it a go there.
Thiago would still walk into the current midfield over Rakitic.
He brings a lot more defensively than Thiago. And with Iniesta, Silva, Isco doing the playmaking, he doesn't have a place in the first 11. We'll see at the World Cup, but imo he won't make the first 11 in the big games.
One of Thiago's major improvements is his defensive work which is better than every Spain midfielder bar Koke. Obv not counting Busquets.
Problem with Koke is that he's not recovered since the second CL final loss and Thiago has long surpassed him in the pecking order with Lopetegui.