[rip_netrunner]

Probably because it's still incredibly buggy? That's my impression watching some of the videos posted to the counterstrike subreddit.

[paavohtl]

I don't think the engine itself is buggy, or at least not all parts. Source 2 has been used in Dota 2 since 2015 and they also shipped Half-Life Alyx using it in 2020; neither is consider particularly buggy.