These days many people could start a company if they wanted to. Direct costs (not opportunity costs, founder labor, etc) for the sort of low capital investment entrepreneurial ventures that catch all the attention are in the $5-20,000 range. That is roughly the amount of money taken to answer the question "is this worth chasing any further?"
Similarly, many people could fund the answer to an important piece of scientific research if they so desired. Biotechnology is cheap nowadays, and only getting cheaper as time advances. The range of $5-20,000 will buy you a postgrad who knows what he's doing and lab access for long enough to answer an interesting question or produce a proof of principle - roughly the same as "is this worth chasing any further?" Can you use lasers to destroy lipofuscin inside cells, for example, or indeed many of the projects approved for the SENS Foundation undergraduate academic initiative.
While for-profit startup costs are well known and a great many well-oiled structures exist to match up funding sources and entrepreneurs, the comparable early stage and low-cost situation for scientific research is very much still in the dark. There are few organizations or initiatives that could be compared with those in the for-profit startup space, working to generate interest for early stage funding of specific low-cost but important science projects.
We can ascribe some of that difference to the lack of a profit motive - you're not getting a direct and bookable financial return on your investment. But put that to one side and consider this: why do people give five figure charitable contributions to cause-focused intermediaries (e.g. a cancer non-profit, or the SENS Foundation) rather than find early stage, important projects they would like to fund themselves? I don't think we can blame that on complexity or lack of knowledge, given that angel investors looking at for-profit startups are in exactly the same position of ignorance regarding the vast range of potential projects to invest in and the huge complexities of their industries.
No. I think it's the infrastructure - or rather the lack of infrastructure surrounding early stage scientific research. The web of relationships, technology, and eager passage of information that enables a dynamic start-up culture is lacking for early stage research. A yawning gulf separates research communities from the many purses that might be opened were the connection made. People donate to research via intermediary organizations with broad goals because there is no readily available, widely understood way to do anything else.
As we move into the second decade of this most interesting century, the cost of answering questions and producing important new results in scientific research will continue to fall. The breadth of important, game-changing work that could be accomplished by a post-grad in a few months - already much larger than people think - will increase. There is a tremendous, growing incentive to open up the whole early stage funding situation for far greater transparency and outreach. The more that people can see exactly what they are funding, the more they will become involved.
This principle of involvement is presently being demonstrated in the broader non-profit space. Things like Kiva are one example, but others that are purely donation focused exist as well. I see no reason why such an effort could not flourish for branches of life science research - and in particular the longevity science that is important to us all.