It was a "PC-community", people really focused on their PC. Its hardware, its OS, how to squeeze as much power as possible out of it. The perfect CONFIG.SYS and AUTOEXEC.BAT for each game, which hardware to use/buy next etc.
And THEN they played games. But they also hung out with like-minded people, exchanged alot of knowledge, data and content which would have been impossible to get by just going online with some modem.
The more this complexity of HW/SW was reduced, the more this breed of "consuming" gamers grew who only wanted to play games and didn't know/care that much about the hardware running it (other than wanting it to look colorful and pretty some years later).
--> If all you want to do is play games, the huge effort of hosting/joining a LAN-party is even more of a burden than it was for the PC-community...