4chan is still huge, it just isn't safe like Reddit. You can post at Reddit and not be exposed to awful fuckery, where 4chan has fuckery at every level. People feel more comfortable with Reddit, and that's cool. Not everyone wants to be exposed to the horrors and distinguished mentally-challenged shitposting of places like /v/
Also /v/ definitely has astroturfers, but the number of "ironic" ones dwarfs the number of real ones.