Are we approaching the end of asteroid-discovery?

From the enormous increase of recent asteroid discoveries by LINEAR, LONEOS, Catalina Sky Survey and Kitt Peak, there seems to be an indication that the number of really new discoveries is slowly decreasing. What is the reason for this? Are we approaching the end of asteroid-discovery, assuming that there is a cut-off (gap) in the distribution of fainter and faintest (main belt) asteroids; or is it just the consequence of the fact that most instruments/devices are reaching the magnitude below which the observers have at present not the possibility to extend their searches towards fainter asteroids? From this investigation it follows that we are approaching apparently the end of new discoveries, as the consequence of the fact that the more important asteroid surveys (in particular, LINEAR) are not searching for new asteroids beyond magnitude V=19.5.