It seems like core technology groups have always higher median age. I remember working in small aerospace company and all the programmers were 40+ with leader in his 60s and I was single person in my 20s. Same working in another instrumentation company (average age in around 50, with lead dev approaching 70).

Maybe working on web stuff is still too culture dependent or even just young space to have enough of old people as changing industries is always hard when you are well in your career.