In the past Bo has always had guys who were ready to make that jump. Look at Kaminsky's efficiency as an underclassman. Guys like Leuer, Nankivil, and Berggren were all solid bench players as underclassmen before stepping up when they got the chance.
There's no one remotely proven as a decent backup for Bo. Vitto Brown was terrible behind Kaminsky, one of Bo's worst offensively efficient players ever. And he's their most reliable reserve that needs to step up. Just to have a marginally effective bench, they need Brown, Happ, and three more completely untested guys to be reliable 20+ mpg guys. Bo has never needed freshmen to step up like he does this year.
The consensus is that Bo will succeed because he always does. However it's just as honest to say he's always succeeded because he had proven underclassmen reserves stepping into bigger roles as junior and seniors. The next time Bo wins with heavy contributions from multiple freshmen will be the first time. With that schedule, I don't think he's a safe bet.