The "small monopoly" in this thread is Paul Graham, who created his capital himself.
First-a, he deserves what he has (as far as you can make such a statement in a complex society). He provided some value, got paid for it, he now takes a risk helping others do the same. The only difference between him and me consuming X, providing X+Y value, and using the Y to buy tiny parts of public companies to have some claim on their profits is scale.
First-b, and yes, if someone came and took away my Y for "fairness", I would start working less to just make what I consume. And I mostly /like/ my job, unlike most people.
Second-a, after critically thinking about it, I actually believe it's better for people like him to allocate capital, instead of either some "democratic process", or even worse some semi-elected bureaucrats. I wish we could have people like Bezos, Buffett, Graham, etc. run MANY MORE things (generally speaking, not attached to a particular implementation). We have all of history to indicate who does things better. Second-a-a, even if we were to say "free market is bad in this area, no free market is allowed [e.g. healthcare or housing]" (to be clear, I disagree with that, but let's say we did) I would prefer to install a conventionally-defined-self-made billionaire from another industry to run said area, instead of a govt bureaucracy like we do now.
Third, as others have mentioned you don't have to take his money, you can bootstrap (and then get rich and loan money just like him).
Second-b, combining second-a and third in a more narrow scope, do you think either voters or bureaucrats would fund startups (and, do it better than the likes of VCs)? It has happened, but rarely and almost always in response to an existential threat. Viaweb FAQ says they were financed by angels to the tune of $2m 90ies-dollars. What are the alternative sources of funding you envision in the "fairer" allocation structure for such startups, be it Tesla, Google, or Viaweb, given their success rate?