Economic theory. A rich person earns more money per hour than a poor person (by definition). Money is a representation of value (by definition). In Economics, value earned is at least proportional (if not equal) to value created. So a rich person creates more value in the same amount of time than a poor person. Their time is literally more valuable.
The assumption of a rich person being rich because of the value created may sound plausible, but is empirically falsified for at least the USA and Germany. Statistically, a rich person is rich because she inherited.
Sorry for the late reply, I didn't recognize your answer earlier. Is there some comment notification option on hn that I missed?
The forbes article you quoted is a bit problematic because the data given are voluntary answers. In studies like these there always is the problem of a potentially skewed return rate: Given a return rate of 30%, what is the wealth inheritance quota of the other 70%? My speculation would be that someone who is proud of the fruit of his own hard work (the quoted local business owner) is more likely to answer such a survey. On the other hand some rich person who found a clever way to unofficially inherit parts of the own wealth while avoiding the correlating taxes won't answer such a survey.
At least the second of the blogs.wsj.com studies is self-selected, too. I couldn't find the papers for the two other quotes because the sources were too vague.
It's better to use data sources like tax income of states. IMHO even better is the concept of social mobility (the wikipedia article is quite good: http://en.wikipedia.org/wiki/Social_mobility), as it also encompasses factors like the parents' social contacts and educational chances. The studies cited there all use official, non-self-selected data and sometimes even proper longitudinal studies. In the results presented there the USA has the the lowest intergenerational vertical social mobility of all researched OECD countries (i.v.s.m. means the probability of a child to get into a higher (or lower) class than its parents live in).
Yes, social mobility is not the same as inherited wealth, because it's a result of a combination of inheritance and other factors. On the plus side, the empirical data it's based on is of comparibly high quality. The problem is that monetary (as opposed to social etc.) wealth is pretty hard to measure even given government data. In Germany for example the data for people having income is more or less 100% available. But the richer you are, the less probable it is for you to have income: The money then comes from capital gains, rent etc. These are way harder to measure, e.g. the capital gains could get collected by a corporation and not an individual. The corporations money only gets tapped on demand (=saved inside the corporation hull until retirement). And the child of the owner has a counsulting contract with that company. Legally, thats not inheritance at all, but practically it pretty much is.
Actually it doesn't matter how they became rich. A rich person creates value by investing their wealth in economic activity, which generates interest as a payment back to them "earned" by their investment.
If our example rich person does absolutely nothing except put their money in a bank, and yet earns more per hour in interest payments than our poor person, that rich person is still creating more value in the same amount of time.
Like I said, this is just the theory. One reason why we should never allow ourselves to be governed by economists ;)
For the purposes of the question, which is about the economic effects of saving rich people time, I believe that's incorrect. Rich people leaving money in the bank are creating more wealth (for them), but they are not applying their time in a way that creates value. Thus there's no economic benefit in saving the time of the idle rich.
I just wanted to highlight the theory that a sufficiently rich person sitting on their arse picking their nose is (in economic theory) generating more economic value than (for instance) a medical professional saving people's lives all day.
I first bumped into the absurdity of this when working on a coding contract in 1998. The project was doomed and would never complete let alone achieve its goals, we all knew it, but we'd all turn up, write our middle-layer business functions according to the project plan, and got paid a fortune for it because Y2K had pushed prices up. I met a nurse who had spent her day elbow-deep in other people's misfortune and was earning about 1/10th of what I was. The stark comparison made me rethink a lot of economics 101.
The assumption of a rich person being rich because of the value created may sound plausible, but is empirically falsified for at least the USA and Germany. Statistically, a rich person is rich because she inherited.