Who is to judge how much is and is not enough? Do you want an international tribunal allocating a "fair and equitable" amount of square meterage of various quality levels of real estate to individuals?
While there may be no legal entity making a decision on the question "how much is enough," people are allowed to make value judgements on the actions of others based on how much they personally think is "enough" for said others.
Assuming you aren't joking, why would you trust the members of the tribunal? I have yet to see any evidence that humans have found a way to overcome the principal-agent problem in governing bodies.
Elected == accountable...generally speaking. Of course there would be corruption and errors. I would trust it over a hegemonic oligopoly though. Have to google the principal-agent problem though. I'm not familiar with that term.
How so? It's clear that voters don't know how (in aggregate) to make rational choices.
Given the (for a single example) well-known strong-arm get-out-the-vote collusion between Chicago's elected city officials and Chicago's regional street gangs, I'm not sure that I would trust a hegemonic oligopoly any less.
The book that this is based on is pretty interesting: