That rarely happens. I've seen some pretty decent like local bands, and yes sure, better i guess than most mainstream stuff, but i think any band i've ever loved was at least moderately successful. Sometimes not as successful as they should maybe but fairly successful.
Even without guitar and bass, it's still music. So i'm not sure how its the end of a "musical" era. Anyway, rock music (in its all encompassing definition) has just stagnated. It was bound to happen soon enough, its been the same instruments for decades and there's only so many things you can do with them. And that's including electronic music which is also stagnating. The only reason i think bass and guitar are maybe less popular than before is because it's easier to learn to make music with computers. I wish there were less of those traditionalist musicians around who feel that making music with computers is not music. This isnt 1980 anymore.