After watching the video can't say I disagree with his bet on it never recovering, no other Battlefield has seen players drop off quite like this, not even BF4.
However a few issues with the video, he mentions Bad Company has no campaign early on, of course this is untrue, however since he actually mentions Bad Company's campaign in passing later on in the video I am going to assume he meant Battlefield 1943 as that was released around the same time as a multiplayer only title and got it mixed up in his script.
The other is he tries to frame the plot of 2042 as unbattlefield and political due to having a refugee crises due to climate change... however that is literally what people are fighting over in the much older title 2142, which if we follow that games time line, then 2042 is only 50 years before the second ice age causing the two factions to battle over North Africa. This climate crises was also hinted at in BF4's final expansion due to its link to BF2142. The Climate crises has been part of BF lore for decades now, and with BF4 confirming it 9 years ago I think its unfair to criticise BF2042 for following the preestablished lore inbetween BF4 and 2142.
However all we get for a climate crises are shitty tornadoes so he could have spent time criticising that, what a cop out they where.