So what do you think led to this situation, a deliberate attempt by physicists to play it safe and avoid work which can be demolished by experiment or observation? Or do you think that we've just run out of easy discoveries and have all the basic stuff figured out and that from now on future progess in fundamental physics will be much harder and slower.

I keep up much more with astrophysics and cosmology than I do with particle/quantum physics. The impression I get there is that even though there is no shortage of crackpot theories and speculation, at least the telescopes (mostly in space, now!) are providing us with all kinds of puzzling new observations that demand theoretical response. Unless some really big breakthrough comes from the new big accellerators, I suspect the next Big Thing in physics will come from the observational astronomers, not the theoretical physicists.