Most bowlers, even great ones, do not play on as long as Broaderson. Statham was no longer an England regular and the '65 series was the last one he played. Snow had only just started his test career and was not as fast at that point either. McKenzie was a cut below in class, and in the 1979 series was already over the hill and quite ill.
Anderson, Broad, Walsh, Ambrose, Imran, Akram, Southee, Umesh, Wagner, Woakes, Hadlee ... Chatfield, Cairns, Clive Rice, Proctor, Donald, Dev, Hogg, Trim, Les Jackson even Freddy Brown all bowled seam up with success at ages older or just a few months younger than Statham when he took 5/40 v SA. They're just the ones I can think of so its more common than you'd think.
Neither is Broad a regular but he's still test class. Older players can be selected at crucial points in a series so not being a "squad option" is more a function of their their age. He was still a force.
The comments about Snow sound too much like stats selectivity some people try to use when downplaying a cricketer's resume. I mean I don't mind but let's make it a consistent principle and not just applying it to Pollock. I think we'd all get sick of it soon enough to discard it now. Disagree about McKenzie and Pollock dominated Australia in 2 series prior the 69/70 disaster.
He only played the best of his era. It stands speculation that if he played more often against lesser players his average would've been higher. Undoubtedly an atg and no argument about the quality of the opposition can be used against him.