As Styxhexenhammer pointed out about Google, even the largest companies don't last forever.  The way Reddit has been run under Pao and Spez obviously hasn't made Reddit a more popular platform that people would want to flock to.  Reddit's traffic--and YouTube's traffic--is thanks to content-creators who choose to use the platform, not thanks to the company itself.  This means that the people running Reddit had an easy job--"don't shoot yourself in the foot"--and they failed at it.  Spez even nuked Reddit's legal "we're just a platform" non-liability for content by editing users' comments.