Meh, think Anderson's wicket tally has to give him some brownie points. Plus he's doing it in a tougher era for bowling than McDermott.
Post-Botham greats for England? I'd say Anderson is, Gooch probably (remember he was probably the best batsman in the world for about 3 years), Broad, KP, Flintoff and Cook borderline. And Root will be as long as his back doesn't cause him too much strife.
Even so that's still a fair bit less than Australia, South Africa, India, West Indies, etc..... (and they aren't quite of the same calibre). As for why, Howe has some very good points, especially 1 and 2 (less certain of 3, as worldwide wickets have only really become homogenised in the last 15 years, which tbf kinda leads into Howe's point 1)