Saban now has a higher win percentage than Bear, and has won 4 Titles to Bears 6 in less than half as many games.
I don't think anyone could argue that the level of competition now vs then is much, much higher as well.
One could argue that the longevity and sustained success is part of Bear's greatness (thus why Saban hasn't passed him, yet)... But there is little doubt Saban's resume at this stage of his career decimates Bryant's.
What do you mean by level of competition? Honestly, I would wonder if the level of competition is less even now. Think about it. Saban can recruit kids from everywhere.
When Bryant was the coach, was he pulling the 5 star kids from CA and FL and all other states? There are a lot more kids and schools, but seems like Alabama has a chance every year just based on the recruits they pull in. I am not sure you could say the same thing with many years ago. Probably less top schools, so maybe it all evens out. Honestly, I have no idea, just thought about where Saban can recruit now with ease compared to years before the Internet and 24 hour news/scouting info/etc.