I too love Colorado. I can get on my mountain bike, bring some nice buds and hit up the national forest and hardley see anyone all day. Last week I went on a 6 hour ride and saw 2 people. The off the map places of the national forest are where its at in my opinion, or even some places on the map that people just over look....like 13,900 foot mountains vs. the 14ers. Can't stand hiking with a bunch of ants in a line up a 14er but hike up a 13,900 and you're pretty much just as high and with zero other people. 14ers are cool and all but just seems like people are out there for bragging rights and stature other than just enjoying this awesome place. 12'k foot mountains can be harder than 14ers so whatever. Some places are so busy, you are correct, man....way busier than it used to be. But if I say "I-70 no way" hit up the side highways, stay away from things too close to Denver and Boulder I can find peace and quiet and stay sane. When you smoke as much as I like to, getting away from the people is key. Colorado still kicks ass in my opinion! Just don't tell anyone.
Edit: I love Denver and Boulder too, great places to visit and enjoy them everytime I go! I just like the hills and a slow pace.