However, "everyone can enjoy a life of luxurious leisure if the machine-produced wealth is shared" depends on someone maintaining the machines and the distribution of produce. (Because the opposite of Skynet - an AGI that maintains itself and keeps every human satisfied - is even less likely than Skynet.)
And who is going to work for free while keeping everyone else's best interests in mind?
The fact that, well, nobody would, not really, is somehow missed by people who blame "capitalism" or whatever instead of blaming human nature.