I started to use death analogies with knickers, but I don't want to equate something so trivial with human life. Knickers are on their way out. It took an organization -- the NCAA (or CCA, whoever) to make a strong decision to get rid of them. I think if you look back at all uniform changes, be it shirt colors -- white long sleeves to stripes -- flag colors (discussed), or even stirrups to one piece, I think you'll find that someone stepped up and said "everyone is going to ___" and whatever is changed was gone in a short period of time.
Knickers are very impractical. They don't look better. They are tough to clean in many cases. The only reasons for keeping them around are sentiment, resistance to change, not wanting to replace gear ($$), and not really being wild about the look of pants for football when all you've seen is knickers for close to a century. The last will be the easiest to change once you no longer have to go through a can of spray and wash each month of the football season. Just think: no more trouble putting on two long pairs of socks -- made more difficult when wearing tights; no more having to adjust your knickers; no more 3 different loads of laundry (whites, blacks, and stripes -- now blacks and stripes); no more looking silly after a subvarsity game running into Subway or getting gas; and finally, the most important: being able to crap in your pants after a big blown call without anyone knowing a thing!