alt Hacker News> They are not functionally equivalent, unless there are games I'm not familiar with where custom lobbies are published in a list for strangers to join.
Lots of the mosts played competitive games have that, or third party websites/discords that have links to custom lobbies.
Being able to make friends off-platform and then play with them is obviously not what we're talking about.
I have to conclude you're unfamiliar with what multiplayer gaming was like when servers were the norm.