You do know Steam is a walled garden right? Steam was a direct attack on game ownership in 2004. We lost dedicated servers and level editors in the AAA gaming space as every game was backended (aka reprogrammed client server to deny game ownership).
I remember when Steam first came out and all the outrage about this. I boycotted them for a couple of years in the beginning. But losing dedicated servers and LAN modes was probably going to happen anyway, Steam or not. Computers audiences have broadened from the very technically-inclined people that played computer games in the 1990s. I may be out of the target age group, but I haven't heard of anyone I know having a physical 'bring your own desktop' LAN party in over a decade. When my kids go to other people's houses to play, they are mixing different devices (Android, ipad, Nintendo Switch) and getting some of those to work without a server somewhere else is probably more challenging than most people would bother with, not to mention some of these devices don't have the horsepower to run a server and a game at the same time. Cloud saves are very convenient, the tradeoffs are well worth it for the majority of people.
Steam has proven to be a benevolent dictator, and the Source engines are fairly open as far as engines go- otherwise we wouldn't have Gmod and all the crazy things people do there. There are tons of custom maps for TF2 If they should ever stop being customer friendly, well, good relations with the pirates I have.