Well, this is a reach.  You're speaking on behalf of millions of people just from the ramblings of a few dozen stans you see post on here.  2ndly, not all PS4 exclusives are exclusively single player.  TLOU, one of the biggest games on PS3/4 had a nice and active MP community.   It's underrated actually.  Lots of people rocked TLOU when it came out.
I'm excited to see the MP changes in TLOU 2 when it's revealed fully.
UC4 had a fun MP segment.
UC2 was the GOAT MP game for me back on PS3.  Simple 5v5 TDM with no loadouts, weapon pickups and power weapons on pickup.
I must've put in several hundred hours in UC2 and 3's MP 

  I was so annoyed when they made the remaster with NO MP.  

  That's one case where the Xbox is plain better.  XB1/X at least with the BC allows older games to live on at least(if the servers are still up).
Bloodborne has PVP/Coop
Hell, LittlebigPlanet 1 and 2 on PS3 was pretty much built off of it's MP.  It had a decent SP campaign but the MP was where users could play, create and share levels they made themselves around the world.
The 1st one sold close to 5 million.
and on the contrary, not all Xbox games are exclusively MP.  Halo, Gears, Forza, Ori etc had decent SP campaigns.