IMO the goal of a government launcher should be to push the envelop of technology where private companies cannot risk going. Prototypes not workhorses.
(see page 39 and 40)
But if NASA is expected to explore beyond Earth orbit, well, that's two steps ahead of private industry. The spacecraft and bases and surface operations (the "prototypes") are not things private companies will yet do, but neither are the propulsion elements to get them out of Earth's gravity well (the "workhorses"). EELVs plus advanced upper stages plus depots is the minimum necessary, and an HLV is helpful. In this instance, pushing the envelope is the opposite of what's wanted, since the launcher is just a tool to enable the actual mission. Once private industry catches up, NASA can leave it to them and move on.
Baldusi has explained to me (as I didn’t understand it at all), that USAF/DoD cannot build their own LV if there’s a commercial option available. And that NASA cannot build a rocket less than 50mt to LEO. (I didn’t know that!) .
Shuttle showed that NASA simply doing its own thing doesnt cause private industry to catch up, but only a commercial capability development program will create systems to come online to service specific idiosyncratic needs: EELV, COTS, Comcrew. That type of commercial utilization uplift for BEO can begin on day 1. Delaying it serves no purpose other than accommodating a bad HLV for its groupies and beneficiaries.
In this instance, pushing the envelope is the opposite of what's wanted, since the launcher is just a tool to enable the actual mission. Once private industry catches up, NASA can leave it to them and move on.
A gov't vehicle would not use any EELV hardware. Any EELV derivatives could be contracted as launch services. A gov't launch vehicle is where the gov't buys different conponents and integrates them itself or with help of integrating contractor(s) and launches them from gov't owned pads.
Shuttle side-mount?