Not registrars. The delegation of new gTLDs into the root is the culmination of the first round of new gTLD expansion, an ICANN project that has been going on

Not registrars. The delegation of new gTLDs into the root is the culmination of the first round of new gTLD expansion, an ICANN project that has been going on for quite some time, and has an extensive evaluation process -- see http://newgtlds.icann.org http://newgtlds.icann.org for lots of information on the process. It's likely that there will be a subsequent round at some point in the future. Meanwhile, there are a large number of new gTLDs that are being delegated into the root over the next few months. Soon, gTLDs will outnumber ccTLDs.