To quote Robert Wright from Non Zero: 

To stay strong, a society must adopt new technologies. In particular, it must reap the non-zero-sum fruits they offer. Yet new technologies often redistribute power within societies. (They often do this precisely because they raise non-zero-sumness- because they expand the number of people who profit from the system and so wield power within it.) And if there is one opinion common to all ruling classes everywhere, it is that power is not in urgent need of redistributing. Hence the Hobson’s choice for the governing elite: accept valuable technologies that may erode your power, or resist them so well that you may find yourself with nothing to govern.  

I consider the ruling class as gatekeepers because they control the access of the remaining populace to prosperity. Across time, different entities have played the role of gatekeeper by controlling different facets that can change society’s general prosperity. To name a few, religion by controlling behaviour, government (aristocracy to democracy) by controlling the central currency and freedom of all sorts, media by controlling information,  and the wealthy, by the sheer ability to control deployment of capital, and thereby job creation.   More