Halman, the US military Black Budget (which is many times greater than NASA's entire budget) already has in full development fighter types of aircraft that can reach the lower regions of hypersonic flight! I would say in the area of 4 to 5 mach at least. I do not have to be actually involved nor be giving away any military secrets to know this, just have some knowledge of how the military mind works, and use a little logic!
I have every confidence that with the 10's of $billions of dollars available, and the desire of the US military to be able to respond to trouble anywhere on the Earth in a few hours at most, that the military IS going to solve the basic problem of having a piloted plane take off from an airfield (or even the deck of an aircraft carrier) using normal jet engines and then get up to the lower region of hypersonic flight, and then switch over to scramjet engines. Then such an aircraft would be fully capable of accelerating up to the higher hypersonic region of 10 to 15 mach. And then show up anywhere on this Earth in less than two hours!
The US military is the ONLY organization with either the desire or certainly the funding to overcome the problems of such a system, but I would not be at all surprised to see them achieve such a level in less than a decade. Of course, we all know that in the beginning (just as the stealth technology was, and to some extent still is) that this technology will be indeed highly secret. But we also know that every development of the military similar to this since WWII has eventually gotten into the civilian sector. And while civilian aircraft do not really need stealth technology (in fact, in most cases civilian aircraft want to be seen by radar!), The ability to travel in the hypersonic region will be a great key for civilian aerospace developments!
Once such aircraft can get up to such velocities, and at altitudes of 100,000+ feet, then it becomes relatively easy to place small aerospike rocket engines on such vehicles (remember linear aerospike engines can take the shape of just about any kind of rear end of any flying vehicle). Ignite such a rocket and get the extra 10 mach to 25 mach or orbital velocity then becomes relatively simple.
It would not require a very powerful rocket, or very much fuel to achieve orbit once the problems of achieving higher velocity hypersonic scramjets is accomplished.
Then it becomes just a problem of scaling up such vehicles to carry more weight in either people or materials or both to accomplish the "Holy Grail" of machines capable of flying from the earth's surface literally into LEO!
NASA could never accomplish this, as NASA's funding is insufficient to develop such technology, and at the same time continue with all of the other things that so many people want NASA to do. But the military (and especially the Black Area programs) do not have such restrictions.
Remember it was not NASA that developed the EELV program that resulted in the Delta IV and Atlas V rockets, it was the Air Force (and that program was not even that secret, nor even a Black program). This EELV Air Force program was not meant to revolutionize the launching of rockets, just bring down the very high (over $10,000 per pound to LEO) cost of the Titan IV Heavy series of rockets that the military had to depend on to launch heavy spy satellites to GEO orbit.
What the Air Force did in that program was to have both Boeing and LM develop large rockets whose major goal was to reduce by as much as current levels of technology would allow, the costs of placing satellites into orbit. And the program succeeded admirably as the cost to the military and other governmental agencies for such launches has been reduced to less than $5,000 per pound to LEO. And if the satellite launch market had remained robust enough, the methodologies developed by Boeing/LM for the assembly line construction of those rockets would have brought down the costs to less than $2,000 per pound to LEO. But unfortunately that did not happen at that time, nor certainly not now with the world's economy being what it has become.
But, I fully believe that eventually this reduction will actually happen, and with spacex possibly joining in, the price of placing a pound of materials into LEO with large conventional rocket boosters I fully believe will come down to the somewhat magic amount of lower than $1,000 per pound to LEO, thus opening up far more business into space itself!
And I also believe that the military will once again come to the rescue by developing the true NASP type of craft, that eventually will bring the price of placing both people and materials down to even far lower levels.
IN the meantime NASA needs to keep up the imaginations and hopes of ordinary people by getting us back to the moon, and then going on to Mars. That is NASA's true calling, it is to be at the cutting edge of taking us outward bound ahead of all others (with the possible exceptions of the excellent space programs of other countries throughout the world), and allowing both the military and eventually pure private for profit interests to eventually follow up to give humanity a true space faring civilization!
So there is really a whole lot more hope than I sometimes see exhibited here on these boards!