Indeed, it is strange that nobody questions why work hours have been reduced to 40 hours and below, a fairly natural trend in a society with real GDP per capita growth rates of around 2%, but then started to rise again. It is perceives as totally natural while it actually isn't. Capital is happy about it in the immediate economic sense (
labour's share of income decreases) and in the indirect political sense: overworked citizens have no time or energy to do political work.
Keynes, a guy who made money on the stock market and wrote that Marx misread Ricardo, i.e. not a crazy leftist prophet but a centrist liberal,
wrote about the future reduction of workhours (
this is a good modern follow-up). The economic world of Trek, not working at all anymore out of necessity, the step from work as a means for consumption to a means for social contribution / self-fulfillment, is just the next step. And unlike working like crazy and then being too exhausted to do anything but passively consume and perhaps enjoy one hobby it sounds like a better life.
About work incentives, they are overrated. Socialism didn't fail because of work incentive issues (they existed but were of minor relevance and compensated for by Western inefficiencies like lack of competition on output markets) but because of the absence of a capital market: companies couldn't fail. Interestingly the problems we face today also have more to do with a badly functioning capital market than with lazy, shirking workers.
So yeah, I have no idea where these obsessions with work incentivzes come from. Somehow people are masochistic, they prefer a world without democracy in the worldplace and the constant fear of job loss to either a full employment world where they could actually tell their boss to fuck himself and easily change the job or a post-scarcity world in which they could merge work and hobby.