Whatever you do now, anything, is not just your own genius but its the accumulated genius of society. It would be quite literally impossible for anyone that "cures cancer" to have done it on their own. Not only it is extremely unlikely that they could do all work just by themselves (though possible) but they will have to rely on the work others have put through out the years... Work that in most cases has been funded through tax money!

So why would one person at the end of the line get to benefit so much from the collective work put by all of humanity to that point?