> We fired ~40 sales people out of over 1,500 in our go to market org. That’s a normal quarter. When we’re doing performance management right, we can often tell within 3 months or less of a sales hire, even during the holidays, whether they’re going to be successful or not.

Which sounds like they have an implicit probationary "we'll fire you in <= 3 mos. if you don't make a sale" that--according to the video--isn't communicated by managers or written in hiring contracts.