Maybe in your district this is true (and some districts are more homogenous than others, for sure), but I'll challenge you to really take a look at the candidates of your next primary election. You'll probably find find meaningful differences between their political philosophies, even if class isn't among them. As an example, though, AOC and Joe Crowley are different in many meaningful ways. As are Connor Lamb and John Fetterman. These are cases where I think people of the political insider class were defeated by challengers that people didn't think fit the proper mold.