That's a very typical uneducated salesperson type of thing to say. The idea is to create a bit of uncertainty and doubt in your mind, so you'll steer away from that brand.
By this argument, we should assume that a Ford is the best quality of car on the market, since they've been manufacturing longer. Toyota, Honda, Ferrari -- they're all amateurs, since they've been in business for less time, right?
Time in manufacturing has nothing to do with it. Quality control, manufacturing process, image quality -- those are the things that matter.
In the consumer digital camera market, two names consistently stand out in terms of quality: Canon and Nikon. Consider these first tier brands.
Kodak, Olympus, Samsung, Sony -- they make fine cameras as well, but generally get lower ratings on image quality and build quality than the top tier guys.
I'd consider Fuji, Casio, Sanyo, and Polaroid -- plus any other no-name brands you can think of -- in the third tier.
(Of course, everyone else who has ever purchased a camera, used a camera, or looked at a photograph may disagree with these rankings. But they would of course be wrong! :) )