I 100% believe that he'd tell people that nobody can win at Nebraska.
That’s the only believable part
I thought that too at first. But the more I think about it, I don't think he'd say that. Saying that would be an admission that he was stealing money from UNL virtually his entire time here. I don't think he thinks that. I think he thinks he got the program close ("we almost beat Michigan and OU and OSU in the same season!") and would have turned it around if he got more time.
I think if you actually ran into him and actually got him to talk honestly he'd say that he had the program 1 step away from being "back" but that political forces meddled with his program and wouldn't support the program the way he wanted to build it.
Having Frost say "No one will ever be able to win at NU from now until the end of time" is how you know this encounter was 100% bullshit. Frost is still a huge NU fan, I guarantee you he doesn't think that. As pissed off as he is at Alberts, I guarantee you he doesn't think that NU is a lost cause. Pelini, yes. Callahan, yes. But not Frost. Hell, even Riley would probably tell you that he could have gotten the program back if we only gave him 2-3 more seasons.
Remember, this is the same Frost who used to randomly call into Omaha radio stations bc he was so fired up about Husker football. His fandom would not allow him to think NU football is dead from now until the end of time.