I know that money is always the problem, but it seems to me that the most useful projects would have been:
1) Rail line from Union Station to Boulder;
2) Rail line connecting Union Station and Civic Center Station (subway? street car? it's only two miles), thus eliminating the Mall Ride;
3) Rail line from the airport to Union Station (which was built as the A-Line);
4) Real rapid bus transit / streetcar / light rail from Union Station to CU Anschutz
5) Rail / light rail service from Union Station to Golden, CO (they got MOST of the way there...)
I understand that RTD's mission is to provide regional transit solutions and the 'biggest bang for your buck' projects are all intracity projects exclusive to Denver. Hell, the A-Line, bus transit along Colfax and a 16th Street Mall Collector pretty much wouldn't have to leave the boundaries of Denver County/City.
Perhaps the real problem is that RTD doesn't have enough funds to do proper regional rail, whereas Denver needs its own separate transit agency. Unfortunately it could never afford these projects so we're stuck with a 50% solution that doesn't really work for anyone.
Then again, there's one school of thought that believes within 10-15-20 years, we'll have self-driving & electric Ubers that will effectively replace the need for mass transit (one of many examples:
https://www.citylab.com/transportati...ns-too/502430/). In theory, self-driving cars could be given their own priority lanes on highways / major arterial streets allowing them to bypass regular traffic. As they're self-driving, they'd be able to drive closer together than each other and brake/speed up more intelligently, thus not resulting in the normal congestion that human-operated vehicles create.
I'm certainly in the "I'll believe it when I see it" camp, but there is something to be said about the flexibility of a ride share-on-demand model that trains and even buses don't have.
I think there will always be a need for rail between destinations that lots of people travel, such as the airport and downtown, but maybe we really don't need rail through Aurora or out to Golden. Perhaps a combination of better bus routes, Uber/Lyft and self-driving cars can fill that need.