Actually, I wouldn't be that surprised at all.
A couple of friends of mine used to be promoters, primarily on the blues circuit, and used to run a major blues festival in the north. I used to help out as part of the stagecrew on the main stages (apart from a couple of occasions when I played at the festival myself). A lot of the acts had British backing bands made up of pro players and I noticed that there seemed to be two types of musicians in these bands (remember that this was nearly ten years ago). The 'old school' guys were forty plus and had come up playing the clubs and the rock and/or blues circuits. They came from a variety of backgrounds, with some having gone to music college but most hadn't. The 'new school' were in their thirties or younger and virtually all of them had been to music college. They all seemed to come from pretty affluent backgrounds with supportive families.
I mentioned Cliff Williams before. When AC/DC started to hit the real big time, they brought in Cliff who is as 'old school' as it gets and went on to become one of the biggest rock bands ever. Now that Cliff has retired (again), they have Chris Chaney covering his spot on the latest tour, who went to Berklee.