In the end it's about a feeling of fairness in society. A certain amount of inequality is probably beneficial as a motivator. But we are getting into territories where wealth is most likely to be acquired by inheritance rather than saving your income, this has to do with the economical and demographical growth rates as well as the typically higher yields already owned capital provides (and secondary the fact that bigger capital stocks tend to have bigger relative yields than smaller ones).

Again, some of this may be desirable, the level of inequality and the fact that this process is not going to slow down soon, means that a growing portion of the population is going to feel that they are treated unfairly.

Capitalists do not actually have to work to make money, that's kind of the point.