Parts availability is a weird thing. I mean, aside from super-rare things like 40-year-old Kawasaki pistons, I just don't worry about it. Like Kiwi said, most everything you need is going to be standard and easy to find even at non-motorcycle places. Like, when my Husky tried to disintegrate on the last ride, half of everything we needed was already in the workshop (bolts, loc-tite, etc.) and the rest was fairly easy to find. The only real "bike part" we're dealing with is an axle, and we're only doing that because we happen to know a guy who has a spare one laying around. If we needed one, and if we didn't have one, there are websites to find something like that, made new and wrapped in plastic. I hear tell that a huge number of parts for old Maicos can be had by literally calling up Maico and ordering the thing, and it ain't going to take no nine months to get it. I really can't imagine that a 2010 bike could be harder to get parts for today than a 1978 bike is. It just can't, unless someone just disbands their customer service department entirely.
So yeah, I'm with Kiwi I don't think it's a big deal. However, everyone worries about it, and that's enough to seriously put a dent in sales.