Michael Powers,
I think irrigation systems were the early culprits in narrowing fairways, followed or preceeded by the tree planters.
Johnny M,
If I were a member of a golf course that hosted a tournament every year, my advice to the club's leadership would be to make sure that the golf course is properly prepared for the membership 361 days a year as opposed to being properly prepared for NON-members for 4 days a year.
With respect to moving the rough lines, its usually dependent upon the geographic location and time of year that the tournament is held, and, it's fairly easy to recapture the wider widths, UNLESS a course has planted their roughs with grasses dramatically different from their fairways.
Upper Montclair made the transition routinely, every year, for decades, when they hosted a PGA event.