A post from 2005 in the NY Times which discusses the thinking and motivation of wealthy entrepreneurs It shows that even if there is great wealth created in the future that there will be significant numbers of people who will still be highly motivated to continue to try and create the next big thing.
One interesting development from Facebook being valued at $15 billion is that Peter Thiel, likely owns 5-7% of Facebook.
Peter Thiel put $3.5 million of support for the Sens life extension research and prizes.
Peter made that donation when he had a net worth of about $100 million. A successful IPO for Facebook in 2008 would likely place Peter's net worth north of one billion dollars. This will likely be increase the odds for further support for Sens.