Did I say anything about a grindfest? I said that the fact that the game is structured in a way that people can functionally spend endless money for endless power gain means that the game is measurably worse for people that don't.
You can't realistically grind in DI as a free player or even a moderate spender. The ability to grind is an optical illusion. No ftp player will play the game long enough to make meaningful progression after a certain point, certainly not before that progression becomes defunct by the next release or season.