A buddy of mine and I played Doom forever, heck we still do on occasion.
We didn't have the ability to play direct connect, so we discovered and figured out how to get modem play to work. we upgraded to USRobotics 28.8 DSVD modems, and figured out how to get them to work and how we could talk over the phone line while playing the game. This was all pre-internet days, so I had to figure out the AT Commands to enable DSVD, to dial, to answer etc. fun times. again lots of trial and error, dropped connections, all that fun stuff. and now, here we are where you can pick up a console connect multiplayer over the internet and instantly play with anyone you want anywhere in the world.
people who say there's been no progress in 20 years, obviously don't know where to look.