If you do a cost/benefit analysis, you'd find that Apollo paid for itself a minimum of $3 benefit for every dollar spent. It could be as high as $8-10 benefit. Please note that this is Apollo, not Space Station, Space Shuttle, or ISS.
Among the benefits were: communications satellites, velcro (laugh, but it's a biggie), weather satellites - think what Katrina/Rita would have cost without weather satellites, medical telemetry (this one paid for Apollo all by itself) . I could go on, but the naysayers won't believe the numbers.
However, the Shuttle was a design abomination. We needed - and need two designs: a space truck, for heavy lifting, at over 20Gs, with no human pilot, and a manned vehicle, which can rendevous with what the heavy truck puts up.
Further on, we need moon, asteroid, or Mars mining facilities (watch the wackos go ballistic) so we can minimize the mass lifted from Earth and also second-source vital supplies.
After that, need a low-acceleration vehicle for interstellar transport, with a computer system that can survive more than 40 years. Maybe an Amiga.
Your two-step process makes sense to me. Save the tare weight for the reentry vehicle only. Put up the heavy stuff with single-use launchers. I know the Russkies were going in that direction with their Soyuz for manned applications and the "Progress" cargo modules. We could probably do better than Soyuz on a reusable crew vehicle. I know there were concerns in the beginning about doing things separately and having something happen to one or the other, thereby blowing the whole mission. But that happens anyway if you lose the shuttle on a mission, so its kind of a wash on that.