Giving Pledges for NewSpace Development?

On Buzzfeed via Drudge, I saw news about giving pledges most notably of which Bill Gates and  Warren Buffet are pushing billionaires to pledge to give up to half their wealth to charitable causes.   Dubbed the "Giving Pledge", the concept was made public in 2010.
But what if some of these billiionaires were to give some of this wealth to development and commercialization of space?
If the Forbes 10 gave maybe 5%, that would amount to ~$23B for space industry development, more than NASA's annual budget (FY2012= $17.8B).  Throw in the Forbes 100 or 1000, we're talking real money.
If concentrated on one or two concrete objectives, such money may make a difference in commercialization and colonization of cislunar and interplanetary space.  Dennis Tito's planned Inspiration Mars mission to perform a flyby of Mars is projected to cost $1-2B, well within the affordability of just 1 or 2 of the Forbes 10 to fund.
The fund needn't be only for charity either.  Such an initiative may well be organized as a consortium of investors/donors and other organizations.  Technology development and resulting IP and high-tech product spin-out companies can be owned by this fund which would then make returns to its investors.  Commercial projects and infrastructure in space would also be developed and owned by such consortium which would be paid for use of infrastructure by companies and governments wanting to do business in space.