Because they were too bloody small, that's why. I am short of 6ft, but couldn't sit straight in a Routemaster double seat, it was incredibly uncomfortable. And more than once had to look at my toes to avoid getting imbroiled in one of those 'sideways-seats-at-the-back-are-for-4-people / no-they-aren't-there's-only-room-for-3' arguments. Sorry. I know they were pretty, and I liked the hop-on, hop-off thing but I was perfectly happy to wave them bye-bye. Oh, and on the hop-on/hop-off thing I've heard (2nd hand) of someone who fell off one misjudging her step. While holding a baby... I'd judge it was her own fault for being stupid, but in today's climate that sort of thing means elfnsafety probably wouldn't approve.