You are quite correct. However, NASA has been working on a space plane since the 1970's without success. Although the Dynasoar program helped with the space shuttle, it was also supposed to lead to a space plane as well. As we have all come to realize, the shuttle is overdesigned and is much more fragile than it seems.
I'm not for permanently grounding it or anything but we are over due for a replacement which isn't on the horizon in any form. If we can get more commercial civilian involvement, we may be able to kick start our lagging space program.
Remember, it was private enterprise that started aviation as we know it, not the government supported program. US rocketry was also pioneered by a civilian.
Just my .02
accomplishment!!!