There seems to be several diferent issues that need to be separated
> As mentioned, "fair representation" would be 4000 Representatives.
why have to be 4000 to be fair ? legislature usually cease to be effective above 700, so limited representative is a must.
> 3-4*50 is a lot less than that.
Not 3-4 per state, just larger state can move to PR by changing district size to 3-4 rep per district
> Besides, representing also means you move to DC right? It means that if you sit long enough on your seat, you become alien to what did matter to you. But that is a unrelated issue.
Well, in theory you should care about voters on your district, or they won't re-elect you. As a city boy i am biased, but i think gov should support where majority of people located anyway.
> And on the top of that we have the defaulters: It means that a incompetent party will automatic get 20-30% of the votes anyhow, making them unaccountable for their mess ups
I agree with commenters above that some people always stupid, its not profitable to deprive their voting rights. democracy is worth giving idiot voting rights. beside if incompetent party become part of coalition gov, they will likely blamed and losing vote when there are economic slump or natural disaster. most defaulters will support gov party if their live okay, and blame them if live turn bad.