It is difficult to do much about them when you have a duopoly on elected government, and a big part of both parties' power-broking is doling out lordships to a) their former notable MPs/ministers and b) their mates. The lords suit the commons just fine. Even more so since Blair's reforms, which increased the number who were purely cronies, relative to the decrepit remnants of the landed aristocracy (which only benefited the Tories).