You're all overlooking how the money in magic is actually made. Sure some people have pulled in hundreds of thousands of dollars in tournament winnings, but people aren't making money off of tournament winnings.
They make their money by using their tournament winnings and continued success and then leverage that by content writing/theorycrafting/appearing elsewhere. Just take a look at
http://www.starcitygames.com/ and look at all the pros/former pros that are being paid to write articles for SCG. On top of that, some of them (like chapin) have written books to further supplement their earnings.
Winning a pro-tour or worlds title is nice and all, but when the top earners have made under 400k in their lives, spread over the last 15 years that's not exactly enough to live on and have to do nothing else (unless you live in shit/squalor and live off of ramen). Sure those that play poker can win considerably more, and THEY can liv off their winnings, but not all magic players are successful poker pros.
Most earn their paychecks writing about magic for other sites or use their winnings to go to college/open up businesses etc.
Contrary to OP's narrative, having known some of these people they are not basement dwelling sperlords like the magic players you may encounter on Friday nights at your local gameshops. Most of the people winning tours and making a living off of magic are older, know they cannot live off of prize money alone, and generally pretty intelligent.