That's the point. "Useful" to whom? If all you care about is money, you might as well go crawl away in a hole somewhere to die, pinching those pennies in enfeebled fingers. Real visionaries, the people who actually contribute to the advancement of humankind, know that learning, understanding, and wisdom all spring from the same source. Expecting immediate, monetary payoffs from efforts that, by their nature, have long-term, sometimes unforeseen, benefits, is the hallmark of a civilization in a state of decay and increasing decadence. Like I said, think small, be small.
I would agree with you if I thought the shuttle and the ISS were anything more than a politically inspired waste of money. I'm actually a big fan of space exploration but we've been off track since Apollo except for the robotic missions which have returned an abundance of science. Maybe Griffin can get it back on track but I'm not willing to bet against future political interference taking us down another dead end road.
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.
That perfectly describes NASA lately.
We should have settlements on the moon by now.