Here is an interesting article on the excess of PhD students in particle physics.
The numbers make the problem clear. In 2007, the year before CERN first powered up the LHC, the lab produced 142 master’s and Ph.D. theses, according to the lab’s document server. Last year it produced 327. (Fermilab chipped in 54.) The two largest particle detectors fed by the LHC, the A Toroidal LHC Apparatus (ATLAS) and the Compact Muon Solenoid (CMS)—which both independently spotted the Higgs—boast teams of 3000 and 2700 physicists. By themselves, the CMS and ATLAS teams minted at least 174 Ph.D.s last year. That abundance seems unlikely to vanish anytime soon, as last year ATLAS had 1000 grad students and CMS had 900.
In contrast, the INSPIRE Web site, a database for particle physics, currently lists 124 postdocs worldwide in experimental high-energy physics, the sort of work LHC grads have trained for.