Human beings are just bigger than when Tiger Stadium was first built due to better nutrition, fast food or whatever. I'm 6'3 250 pounds and there is no way I can squeeze my butt into a 28 inch wide seat without overlapping into somebody elses allotted seating space. I know there are people a lot bigger than me that go to games. They should take that into account when figuring seating capacity before we get disciminated against like a guy I know who is over 400 pounds and whenever he flys anywhere the airlines make him pay for 2 tickets.
LSU has seating for handicapped people. If a Tiger fan is far too large to fit in a standard bleacher seat, there are chair seats in the fieldside boxes. You can even bring your own chair. I knew a 350-pound professor who sat next to the field in a steel folding chair. Not a great view, but he didn't have to walk up the ramps either.