Really? Pinterest is ranked #16 by Alexa in the US for internet traffic[1]. Do you really think running such a site with that much traffic doesn't require top talent?
Come on. This is not like Cancer research. Its a solved problem.
It's a solved problem in the sense that the 5% of work that yields 95% of benefits have already been done. But because of the massive user base small improvements at great cost can be worthwhile.