That is indeed an oft raised concern, and there are certainly cases where this seems justified (although much of 'the people' seem to keep voting those delegates back in power, so perhaps they don't mind?). On the other hand, an electorate that expects to be 'served' as an errand boy would serve them rewards politicians who say what the people want to hear. And that is of course where you get politicians in power unwilling or incapable of delivering what they promised. They usually 'solve' this by means of deflection: conjure up some enemy and/or blame someone else for their failure. That's something we're seeing a lot of lately.
It will be interesting to see (from a safe distance for me, fortunately) how 'leave' voters will approach the inevitable victims of Brexit. Are they going to tell people whose business collapsed or lost their jobs 'oh well, cheer up, at least we've got our sovereignty back!'. I predict not. They will say it's all because their errand boys in London messed up Brexit. Disown...disown....disown. The only way out of that is to have Boris and Nigel carry it out, I think. But yeah, the price will be high just to prove a point. I don't wish that upon you.