Thats because there is a lot involved in painting a bike. Most people do not know how to paint bikes. When we are done with a bike it looks brand new. As far as time we have been tested there too and they still look good. I've seen a lot of bad paint jobs from guys that paint cars and so on. You can't treat plastic like a car.
We've been doing a lot of new bikes lately, we have a couple 01 R1s and R6es in the shop right now, and you can't tell the difference between new and ours painted. The only big difference is we paint most decals. You would be supprised how much of your bike is a piece of paper. We paint these on (except letter stickers ie. Suzuki, Honda, GSX-R, CBR.....) It looks a lot better because you can only make a piece of paper shine so much. We usualy only put stickers on bikes that we are only doing half of. That way it's an exact match to the other side.
Check out our examples on our page, we have a bunch up there right now. check out the 01 ZX9, thats 100% paint including all of the color fades.