When you say "Their guys" it suggests that different generation has their "favorites," which implies it is based on attitude, and not actual performance.
You have to judge a player by their performance given the context. I have gotten into it in the comments on Youtube of some highlight films of Jim Brown. You have all these people saying Jim Brown would be so great today. Well, I'm skeptical. Look at the competition, the defenses. I see relatively small, weak, slow defensive players trying to tackle him. Somebody pointed out that the typical defensive lineman from the late '50's, early '60's, was around 230 lbs. I'll be a good number were under six feet, too. I remember the sizes of the UM teams in the early sixties. A big offensive lineman might be 235 lbs. That was very big in the era that our great George Mira played. Do you think we were stacked with WRs and DBs running typically 4.4-4.5's?
Some of our teams in the early sixties had offensive linemen under 200--I think our starting center Bob Hart was 195. He competed for a position with Bob Dental who was a big 220. I remember when some of the great Bear Bryant teams of the early '60's had DL's well under 200. But they were known for speed and fierceness.
So, when you judge who was the "greatest" all time UM players, you should consider in terms of the era. Don Bosseler was exceptional for his era. He rose above most with whom and against whom he played.
Many of today's players come in with much better physical attributes, people grow bigger, faster and stronger these days, and then they have better training, nutrition and medical care and rehabilitation. A friend who played on the very good Hurricane defenses of the mid-late '60's told me that weight training was not "compulsory", it was voluntary. A good number probably did not lift. When I was in high school, some coaches did not believe in weights because it was thought you got too tight and "muscle-bound." The latter is a word you never hear anymore.