Certainly way faster.  But carry more people is a big question mark.  The T-Rex light rail line and the additional lanes on I-25 combine to carry a LOT of people.

And of course building/expanding a major corridor in a fully-developed section of a major city is gonna be FAR more costly than building out on mostly-undeveloped prairie between DIA and Greeley.  That would be true the other way around too (i.e. if they tried to build hyperloop through the middle of the city rather than out on the open prairie as proposed). 

Hopefully the $3B estimate is just a SWAG and is way high (even though cost estimates tend to be off in the opposite direction).  One would hope that prefab tube sections would enable the costs to be much cheaper than that.  If it isn't, it could be DOA even if we are picked.