People who have been to Fort Collins know that that city needs a _lot_ of infrastructure work to become anything more than it is now. FC already bulges under the pressure of college move-in/out and tourism there is fairly big for Coloradans. I also don't think residents are the kinds that would go for large expansion. Denver still has more than enough room to grow before they push out into the smaller towns, and if they did Boulder would go first since it already has a startup ecosystem IMO.