The The Hiltons, Rockefellers, Waltons, Kennedys, Mellons, Murdoch, Fords, Bushes, and Carnegies are all typical members of the capitalist class. It is quite obvious that these people are in extremely different socio-economic situations than most other people. In a society where the richest 1% has more wealth than the poorest 90% it is obvious that there's a big difference between the 1% and the 90%
We are forced to sell our labor. The means of production, things needed to produce things like land factories, etc., are overwhelmingly concentrated in the hands of a small number of people, the capitalist class, or in organizations they control (like corporations). I'm not talking monopolies of individual companies, but the monopoly of a small group of people over the tools necessary to produce the basic necessities of life. I cannot simply produce what I need to survive on my own because the land, factories, etc. are monopolized by a small group of people. Therefore I must sell my labor to those who monpolize the means of production if I wish to survive. Otherwise I will become homeless, starve, etc. We are thus forced to sell our labor by the threat of starvation. It is not at all voluntary.
The wage contract isn't a mutual agreement for work because the capitalists do not contribute work, they give permission for the means of production to be used. Market capitalism is (theoretically) based on competition, not voluntary cooperation.
Usually, the wage contract does not involve the trade of capital for labor. It involves the trade of labor for a wage. The reason some people have lots of capital and others little or none is because those with lots of capital, or their ancestors, stole it and state intervention is used to insure they keep it. See
here for proof of this.
In a zero-work society things would first be reorganized so as to reduce unpleasant tasks, which would probably include tasks currently performed by janitors. Where possible unpleasant tasks should be automated - this is sometimes not done today because it is more profitable to hire cheap labor. And by "unpleasant tasks" I mean things that everyone finds unpleasant - there are a great many things which some people do not like doing but others do. In such cases the people who like doing it should do it, and the people who don't shouldn't. If, after all this, there are still unpleasant tasks left over that we can't get rid of then everyone should take their turn doing them. To condemn one group of people to perpetually doing unpleasant tasks all the time while the descendants of the conquerers live in luxury is unfair.