As I stated previously on page 2 of this thread about the 2160, "All the features can be adjusted via remote without ever touching it."
Which begs the question on the 2150, how often are you switching the speaker selector switch in normal operation? It is, after all, a mechanical switch. Mechanical components can break from using them. But in a typical set up with the 2150, you have your speakers hooked up and the speaker switch set to one position. I could be wrong here but, doesn't seem to me like it could break without ever touching it. Are you switching between zones with speaker A and B? and therefore using the selector switch more?

I've been in the consumer electronics repair business for many years and serviced many brands. They all can fail in one way or another. You take measure of a company by, if they treat you fairly, for one example, after any failure occurs, whether in-warranty or out.