Lets be realistic
The original X-prize was basically a hack. Since you didn't have to achieve orbital velocity, the problem was how to build a plane that had enough extra boost to go exo-atmospheric. In the grand scheme of things that isn't that hard a problem, and it wasn't surprising when someone won.
The latest X-prize (or should it be G-prize) involves getting something into space, not only achieving orbital velocity, but also getting enough energy into the think for an orbital transition over to the moon. Being accurate enough to get into Lunar Orbit, and then having enough control to descend and land on the moon. Don't forget of course that the moon has no atmosphere to glide or parachute in. Finally, you have to be able to control a rover at the other end - which is probably one of the easier parts of the mission to be honest. There are reasons it cost billions in the first place, and hasn't been repeated by anyone since. Its damned hard, and not that useful.
If someone genuinely wanted to promote private exploration of space, the next prize would have been a logical continuation of the original X-prize. For example, launch a small object into low-earth orbit to transmit back to earth. Basically achieve the same things as the early Sputnik missions. Once you have that nailed, you can expand the prize to launching medium or high earth orbit, accurate orbit insertion positions, and then consider moon missions and the like.