If ordinary, Mom and Pop users, don't register and develop sites in a gTLD, then the gTLD will become a zombie TLD with little usage and just renewal fees. Google has demonstrated no in-depth understanding of the domain name business and is just cargo-culting along. The problem is that reserving too many premium domains kills natural domainer interest in many of these new gTLDs because it destroys the whole land rush phase of a TLD's launch. No land rush buzz = no awareness = no reason to develop sites.
Google's main problem is a lack of innovation and too many copycat ideas like Google Plus, Google Buzz etc. Its new gTLDs are no different.
Regards...jmcc