https://store.steampowered.com/stats/

Sorted by active users:

    860,000 - CS:GO
    480,000 - DOTA 2
    173,000 - Source SDK Base 2013 Multiplayer (Mostly a multiplayer GTA mod)
    146,000 - Apex: Legends
    130,000 - PubG
    112,000 - Rust
    93,500 - Destiny 2
    88,400 - GTA V
    76,000 - Rocket League
    67,000 - R6:S
    62,000 - Football Manager

I think it's pretty clear that competitive multiplayer games are the gaming zeitgeist (On the PC). Rust, Destiny 2, GTA V + mod, and Football Manager are the only titles in this list that are really played in a non-competitive manner.

Now, its true that in terms of copies sold, competitive multiplayer games are not quite as dominant.