Denver is only recorded as "not dense" because the city technically includes all the land around the airport where there is very little built. If you don't include the airport property the density is pretty close to San Jose.
If we are discussing tech hubs, then the surrounding area should be included such as Boulder, Broomfield, etc. Just like we should include Mountain View, Palo Alto, etc. Having lived in both places for ~4 years each, the density in the Denver area is not even close to the bay area.
