This is just completely untrue. Not the part about the Europeans having some very advanced space engines, they do. Very advanced. But the opinion that the united states doesn't (and let's not forget Japan, who also has a very capable space agency).
The US has VASIMR, which could be in effect in 10 years or less as a space tug. It's only capable of operating in Space, but it's exceptionally effecient when doing so. If you are going to be mining asteroids, the VASIMR concept is marvelous. But the US is also exploring RAMjet and SCRAMjets, and is a leader in Ion Propulsion (Dawn Mission).
Thus, saying that the US "only has rockets" is not true at all. Even if it were, rockets are very useful. At some stage in deployment, even the most advanced single-stage-to-orbit Spaceplane concepts (there are no working models yet) need a rocket thruster. The only current systems that could feasibly deliver a payload to LEO that don't involve rockets at some stage are Mass Drivers which are years behind in capability, or momentum displacement systems like an http://en.wikipedia.org/wiki/Space_elevatoror http://en.wikipedia.org/wiki/Space_fountain.
I'm not saying the US is the most capable country in the world right now when it comes to space exploration. They may very well have lost that position to Russia or ESA. However, NASA and the US are still very capable. Plus, NASA is doing everything it can to get private US companies into space, and doing it well.
I've been watching the SKYLON project very closely. While it is fascinating, it's still a long way from construction. I don't see any way they could get those into production by 2020. They have yet to even prove that their engine concept will work. Besides that, it's a veriation on the SCRAMjet and many countries and companies are working on their own versions. This includes the US, who got one to http://www.newscientist.com/article/dn12075-scramjet-hits-mach-10-over-australia-.html. (Joint venture with AUS)
I like the idea of VASIMR, but I still needs conventional rocket technology to get into space and that is unbelievably expensive. Once in space it is a fantastic concept but for mining a spaceplane like Skylon is still a better option, mainly because Skylon can reach a Near-Earth Asteroid faster. As for Mars and beyond, VASIMR would be quicker. This is because of VASIMR's continuous 6N thrust and long burn duration gives an eventual ultra-high speed, eventually it would catch up and over take conventional rockets which could only work in short bursts for a low duration of time. As this level of thrust is not enough to even get of the ground, America is still 100% reliant on rocket technology which is just too expensive. The only way ionised plasma engines like VASIMR will be used will ironically be under transportation of a Skylon like spaceplane to deliver the engine into orbit ready for assembly to the body, which also has to get up there somehow. Rockets can do it, but the cost does not add up in a money driven industry. This is what I am alluding to, America needs to ditch the rocket technology because no mining company would take the extra cost when it doesn't need to. It would rather use the spaceplanes to deliver VASIMR into orbit and if the US government doesn't allow non-rocket technology (or non American technology to be more specific) to get it into orbit then nobody is going to the ion plasma engine. That is just how business works.
Skylon isn't far away from the manufacturing process. The engine testing has already begun and it is going very well with extremely postive results. It is also using RAMJet technology, not SCRAMJet, which lends much more use to sub-sonic performance. However even the much faster SCRAMJet technology is not enough to get a vehicle of any size into orbit, they efficiency drop off is rediculously enormous when the engine reaches a certain altitude as there is no fuel in the tanks left to achieve break through, like all such engines they can deplete quickly and the lack of oxygen and hydrogen in the atmosphere, especially hydrogen which is rare at all altitudes and oxygen specifically being thin at higher altitudes the RAMJet/SCRAMJet would stall. Where Europe is lightyears ahead is the combination of RAMJet and Rocket technology in one nacelle. That is basically the only way to get it done using both technologies due to weight issues. Additionally, America has been working on RAMJet and SCRAMJet technology longer than any other nation but it still hasn't found a solution that effectively renders the engine unusable after one flight due to immense heat and pressure forces. Europe (Reaction Engines) is currently in the process of proving they have finally done this, and that would save insane amounts of money for companies because these engines won't come cheap. You can't very keep replacing them every one, two or twenty five flight missions. They have to last for two hundred or more missions. This is why America is still very, very far behind. Not only counting that with the heat issues, they haven't even got a clue how to fit that and a rocket into one single working engine.
So with the Skylon testing looking really good, and funding all but guaranteed for the next two stages of research and development by the combination of pledges from the Aerospace giant Airbus, the UK Government, the UK Space Agency (which some believe was created because of Skylon), the EU, the EU's Framework 6 project, NASA (yup, they are there as well), and general investors... it is well on course for a 2020 assembly timeline.
VASIMR could work, but it won't be profitable if America insists that American rockets transport it up to orbit and that is something that America has been notorious for doing in the past. Just look at the reaction for sending astronaughts up using Russian rockets, imagine America touting their new super space engine only for the public to learn that it can barely blow away a piece of paper when sitting on the lauch pad, and that no mining company wants to pay about £150M just get the engine bay alone into orbit. And going back to the thrust of VASIMR, companies will be far more interested in the Near-Earth Asteroids because it delivers are quicker roundtrip meaning a faster return on investment. VASIMR is the best option for deep space missions like Mars and beyond, not N.E.A. Mining. There is alot money in mining, not so much in scientific exploration. This is why I am saying Europe is lightyears ahead on the commercial aspect of space... not on the scientific aspect of space.
I also don't think Russia and ESA are necessarily ahead of NASA neither, I still believe NASA is the front runner by a large margin at this point in time. Just because they rely on other nations to take men to space does not mean that at this moment right now that NASA is a wonded bull, they are still by far the class leader for rocket launches. The US alone has about 40% of global launch trade, that is pretty dominant but that will end ofcourse unless an American company changes it's gameplan.