You can get a lot of things by doing something to earn money, then using the money to buy the thing. One large exception to this is things in the very near future, since the process of earning money and spending it takes some time. So one big reason for being disinterested in earning money would be that you have a very short term focus.
The usual reason people give for being disinterested in money is nearly the opposite: that they are inordinately interested in big, important, deep things and thus have no need for such a petty mundane thing as money. Money is presumably useful in seeking such big goals, since it can at least buy you out of other mundane concerns. But let’s suppose these people are right, and money is less important than usual in this realm, for instance because there are other inputs to deep important goals, that money can’t buy.
Then we should expect people who are especially disinterested in money to be well represented at both the ‘very near goals’ and the ‘very far goals’ ends of the spectrum. My observations of humans suggest at least as many would be at the near end as at the far end. However almost everyone who isn’t very motivated to earn money seems to cite being at the far end as reason for disinterest. Should we believe them?
Meteuphoric 
A primary reason for earning money is because you’ve learned that it sucks to let short-term impulses go unfulfilled. People who develop cocaine habits, for example, often become obsessive about earning money. It’s more operant conditioning than long-term focus.
Long-term goals always need to be sublimated into short-term operant conditioning, whether your long-term goal is a beach house in La Jolla, a novel mathematical proof, or to never be without your next fix.
Some individuals borrow extensively on their credit cards. This paper tests whether present biased time preferences correlate with credit card borrowing. In a field study, we elicit individual time preferences with incentivized choice experiments, and match resulting time preference measures to individual credit reports and annual tax returns. The results indicate that present-biased individuals are more likely to have credit card debt, and have significantly higher amounts of credit card debt, controlling for disposable income, other sociodemographics, and credit constraints.
Source: “Present-Biased Preferences and Credit Card Borrowing” from IZA Discussion Paper No. 4198, May 2009
Yes MoE, but what about the people who regard taking the time to spend money, or to even determine what goods are for sale, as too much of a nuisance to bother with.
I think that was the point.
To put this more simply: Are people who don’t study/work much impulsive and lazy?
I would say disproportionately yes. But my experience is that there really is a subset of far oriented and intelligent people who find leisure more satisfying than consumption (at least more than most). For example, you.
I question your premise. Many people have told me that money is not very important to them because they value leisure time more than the luxuries that money can buy.