In general, scholars in the hard sciences are in a better position than other academics. There is often a market for their research. So if university life doesn't work out they have other options. For those who decide to stay, though, getting funding for projects can be difficult--particularly for not-yet-established younger scholars.
The Chronicle of Philanthropy has a story about a new initiative called Fund Science, "a small nonprofit organization that asks the general public to help finance the work of young scientists." Launched by David Vitrant, who recently received a doctorate in genetics from the University of Pittsburgh, "The group addresses the very issues that soured Mr. Vitrant on doing scientific research himself—the dearth of opportunities for young scientists, and the gap between the scientific community and the rest of society. His first two grantees have never received federal research money."
According to the Chronicle, "The average age of researchers when they receive their first major grant from the National Institutes of Health is 42." Younger scientists are more likely than ever to have several postdoc positions before they get a real job. And even then the academic market is not very flexible. Tenured professors at the top want to stay in their positions (they want to even more now that their retirement savings have taken such a big hit).
Though universities may want to get some younger blood in the door, they often don't have the room. And then the problem with grants becomes circular. It's harder to get grants when you don't have a long term position as part of an established lab but it's harder to get that long term position because you don't have the research record. Fund Science, though it is still pretty small, sounds like a good way to get around this issue.