Says who? You are overrating these players and/or underrating Serie B/A.
Rovella excels in Genoa. Neither of those 3 would be the best player at Genoa. Ramsey can be the best player for 5 matches a season sure, but that's not really useful to anyone except Wales. Bentancur has been in Serie A for like 4 or 5 seasons now and he isn't blowing anyone away. There are plenty of midfielders better than him. Young and old. Arthur has talent, he can do more, but as of now he only plays a handful of minutes, its not like he is doing much.
In Serie B it is not easy to be consistent. Someone like Arthur would still have to know how to defend, Bentancur would still have to learn to do more with the ball, and Ramsey would still get run over and injured.
Talented players deserve a chance and more often than not clubs benefit for giving it.
If I look at Serie B's best young player award they used to give (2011-2019). Almost of all of these players truly deserved a big chance after their Serie B season, and all that got it succeed.
El Shaarawy, Insigne, Verratti, Immobile, Berardi, Rugani, Masina, Morosini, Cragno, Tonali
Fagioli would likely win it this season. Deserves the chance over most of our midfielders.