It seems like I meet a lot of people from Colorado who are into the Rocky Mountain lifestyle......they own skis, mountain bikes etc. They don't necessarily participate in these sports all that often, but they would like to if they had more time/money. (There are obviously a lot of core skiers as well)
If you are sort of into skiing, a cheap season pass would be hard to pass up.....even if you don't use it to its potential.
By contrast, the Salt Lake City seems to contain a number of people who are really serious about skiing, and a bunch that don't seem to care that such great ski areas are in their back yards.
SLC seems to have fewer casual skiers than Denver. I don't know if lowering the costs of season passes would increase profits in Utah.