The Redditors who are paying lots of money for the scarce handles, and the people they are paying lots of money to (the feudal lords or whatever, I don't know what to call people in this hypothetical Reddit/Urbit mashup), would absolutely lose out if more became available. They would be like taxi medallions, or houses. Urbit itself makes the analogy to real estate, and real estate owners do not have the tendency to say "yay, more neighbors!"
And I don't need to fork Urbit given the people who run it are jerks; I can just run my own normal Linux server, which runs reasonable well-designed programming languages, and can subtract in constant time.