Particle physics had progressed so fast since the 1940's that the particle physics community had developed a system of "preprints" in which people circulated drafts of their papers to colleagues at their institutions and others months before they were published in journals. The story goes that Tim Berners Lee got tired of e-mailing documents back and forth to colleagues at CERN and decided to invent HTML and code a bare bones browser to allow him to (we would today way) webcast his research. There is something about the pace of information exchange within CERN and in the particle physics community that supports the idea that HTML might have taken 5 more years to be developed elsewhere (and it would have been some university or other: USENET and the text-based tools to go with it, and GOPHER, developed in that environment).

The large particle physics laboratories do employ thousands of physicists, engineers and programmers specifically for particle physics experiments purposes, and that is a nonnegligeable fraction of the respective academic communities. If the large labs didn't exist these people would be competing for academic jobs elsewhere and it would result in more people going to industry, as well as fewer people getting doctorates.

If LHC funding hadn't gone through, CERN would have stagnated and maybe shrunk. You need far fewer people to run the existing facilities than you do to develop a new facility, and the LHC research programme is much more intense that what can be carried out at the existinc facilities (not that that isn't useful, too, but it's on a smaller scale in terms of people and resources).

Consider CERN and the LHC a Keynesian stimulus package for physics and engineering.

We have met the enemy, and he is us — Pogo