I feel badly for all of you who have reported that in your experience it's been the "norm" to share hotel rooms with co-workers. I actually don't mind traveling for work, and I realize that may be due in large part to that I get some alone time while doing so. From the perspective of most people I know, they don't see much of an upside to traveling for work, since you're usually spending all of your daytime hours doing the bidding of your employer. But at least at the end of the night, you should be allowed some alone time away from colleagues if you so choose. No wonder so many people dread business travel if they are stuck with their colleagues 24/7.
My philosophy is that if you're going to give up additional time to travel for work, you should get some semblance of a benefit. For me, a dad with 2 small children, having 'quiet time' (read: zoning out in front of the TV in my hotel room) is that benefit! When I imagine having to deal with a co-woker (who I might not even like) in the room with me, all because my employer is out to cut costs....that would change my whole attitude towards such travel.