Those are acquisitive Yuppie-trained Hey Look How Much *I* Spent! for a Muffler kinda guys n'gals. Learning the subtleties about riding is not high on that list. (There are always exceptions, though)
Bet: on the Sunday Morning ride from Stinson Beach --> Point Reyes, these Fashionables will trickle in.. while the riders are on 2nd cup of whatever. The early-arrivals may be on everything from BSA 650s to Norton Dominator 99s - which cost in the hundreds. New. A while back. (Well a few ZX-11 thru 13s on brute HP and some other pukka racers; but these don't need any 'better' mufflers!)
Nobody ever went broke, pricing stuff for the gullible and fashion-conscious Too high.. well, almost nobody. There are no US 'motorcycle' mags I've seen in past several years; just hype like above. It sells. Maybe in UK (?) are some vestiges of The Motor Cycle from days of yore. I hope so.
Still, there will always be a few authentic riders about; it's just too exhilarating - to surrender to the tawdry masses.
Ashton