that The Last of Us Part II (bigger)
so late in PS4 life TLO2 is not as big system seller as Spider-man, i don't think there would be any game that sells more PS4 than Spider-man at this point, agree with the rest of your comment.
PS4 has had a very strong fifth year mostly because: early in the year in japan it got the biggest third party you can get and in the world in general Fortnite popularity boost consoles sales for the early months, God of War was a huge surprise and helped a bit but i don't know if it had that much of an impact but made their half more sustained, and when Fortnite started to plateau Spider-man came to the rescue, which is the exclusive game with widest appeal that has launched in the console so it sell A LOT of systems. RDR2 existing also helped.
Next year will be more rough than this one, there seems to be no new Fortnite in the horizon, Days Gone is not GoW nor close to it, there is no big Rockstar game and not even TLOU2 has a wider appeal than Spider-man plus a lot of the target audience is already on the platform. KH3 is the only title right now that i see having a huge system selling potential and 1. is multiplatform and 2. by huge i mean compared to the 2019 lineup, i don't think it will get close to the big juggernauts of 2018. If you add to all that it will be its sixth year an important decline is to be expected.
Anyways the console this generation has done fantastic, it will probably end between 110-120m sold and that is if Sony hasn't any secrets plans to keep it afloat for longer (aka, PS4 Pro being able to run PS5 games) which will put the PS4 as the second highest selling home console ever. Analyst and people in this forum are just warning that at some point the party starts to end and people should be prepared for it.