"Dynasoar is a dumb idea for an air superiority fighter. It takes one ICBM for one dynasoar, minimum. So, for a fleet of 500, we would need 500 ICBMs, and all their attendant launch facilities and maintenance."
500 ICBM's is/are no technical hurdle. The U.S. has built far more than that, as has Russia. Perhaps you are arguing that no one would bother changing the mission for such devices. You may even be right, but that sort of guess makes for poor defense planning along the lines of "terrorists would never change the mission of civilian airliners into kamikazis" sort of thinking.
And in a world where the U.S. has *already* paid an astounding $26 Billion for a mere 23 F-22's, the costs of a $2 million Titan ICBM would take quite a while to add up to what we have spent on a single atmospherically-limited fighter.
Moreover, the Titan was a way to get an orbital or sub-orbital fighter back in 1960.
As civilians have already proven, there are other, cheaper ways to reach Space today.
Perhaps you are arguing that no enemy would bother, but again, that sort of dismissal of existing, proven civilian technology seems rather unwise in the field of defense planning ("Oh those Germans...they'll never drive *around* our Maginot Line.").
236 - "the costs of a $2 million Titan ICBM would take quite a while to add up to what we have spent on a single atmospherically-limited fighter."
*** ROTFL - Boy, you really haven't got a clue, have you.
That amount of money wouldn't even by an F-4 Phantom 40 years ago (even in 1964 dollars.), let alone all the support costs.
In addition, there are all the support costs, and personnel, and equipment, and maintenance, and environmental.
Minimum costs for one flight of a DhynaSoar to orbit would be on the order of $100-200 million. And the rockets are not reusable, and take months to prepare, and are serious hazards. Launching one shuttle takes about $500 million, on average, plus the costs of the vehicles and satellites.
"As civilians have already proven, there are other, cheaper ways to reach Space today."
*** Yes, there are some cheaper ways to do some things, but they are about as practical as manpowered flight - no payload and no mission performance.
And reaching space is not the objective. Air superiority is.