re: Will Alabama be back to mediocrity when Nick Saban is gone?

It depends on a lot of variables. Assuming that Saban leaves on good terms without managing a decline on his own watch, Alabama will likely be a great program for 4-5 years as long as the coach isn’t actively awful. The quality of the hire will dictate if they can stay great. Of course a “great” program is not what Saban has going on right now. Saban’s leading what is possibly the defining standard of excellence for generations. So the competitive landscape will definitely improve for everyone around them but it won’t be like everyone gets their free hits in on Alabama either.

Everything I read on how the Bryant twilight went indicates that Bryant and his staff really declined in quality of they last few years after the 1979 title. They missed a bunch on recruits and Bryant was in such bad health he lacked the capacity to pivot the program - like he did a decade earlier - once again as football started changing in the early 1980s. It left Perkins in a terrible position because the program was in flimsy shape when he got there.

If people want to see the post-Stallings to Saban time period Alabama that is often exceptionally average to bad, they need to hope that Saban keeps on coaching when he’s lost his edge. He doesn’t seem like the type to do that but there’s your vector.