I have said since the whole "buy in" stuff was first brought up, that if Scott Frost has to choose culture or winning a few meaningless games early on. I say meaningless because in the overall scheme of things, if you end up with 4 or 5 wins you aren't going to go bowling anyway.
The point being, if you are going to play players that are better, but haven't bought into your culture, then you are setting your culture back multiple years. Every freshman from 2018 and 2019 class has watched players, who are believed to be malcontents and not buying in, start and play in games. If the message was sent that this is the culture we want and that is the number 1 priority, and you sit some of those malcontents and players that didn't buy in, then you get more immediate buy in. But if you allow the malcontents to continue to start and play, the younger players see that as acceptable behavior or that it really doesn't matter if I buy in 100% because if I am still better than the guy behind me, I am going to play. Additionally, if you recruit players with a history of poor off the field behavior but only punish continued poor behavior minimally, you run the risk of not only losing that player, but players that watched you punish that player minimally. Each season that is allowed to continue, the next class, in this case the 2020 class, sees that and getting rid of the "cancers" is more difficult.
It is just very difficult to change culture and play your best players. The problem is that most coaches have a big ego and want to win, so they sacrifice culture for wins. Fans don't want to deal with 2 and 3 win seasons, and they will bitch and complain about poor seasons.
So, I guess we can blame Riley for the inherited softness, but right now, after two full seasons, any lack of culture on the team is at the feet of Scott Frost and his staff.