"Those who don't depend on it for their living are free to maintain their integrity."
Why insist on this syllogism? Why must enough money to support a modest lifestyle necesarily involve losing one's integrity? Why is this an argument? Where is your proof that sellout is a rampant force in artistic/cultural production and that money is a universal pollutant?
The myth of sellout is rooted in a puritanical desire to suffer for money and I don't buy it. Your "experimental proof" of the tainting (sullying? dirtying? perverting?) quality of money is equally specious. I know a lot of people who do exactly what they are passionate about for a living, and see no loss of integrity, no lack of fun, no greenish tint of money pollution around their gills.
What I do see is a handful of people who have the freedom to go deeper and with more commitment into their art, and this yields an artistic product (be it music, painting, or aikido) that is more considered, fuller, more of a gift to the greater society.
This crazy notion that money taints artistic production is a relatively new construct bred by a capitalism that has no love for any kind of soul-maintenance that cannot be mass-produced and mass-consumed. Historically, cultural producers (like O' Sensei) have worked for ages within a fairly comfortable system of patronage that influences the outcome of cultural production as much as abject poverty or hobby status does. What do we gain from taking away the money?
I don't trust the culture that is trying to ram 100+ TV stations of crap down my throat when it comes to the value of cultural production. Do you? Really?