Not all games are CS1.6. Some game servers quite literally require access to tens or hundreds of gigabytes of game data, in addition to support from various log

Not all games are CS1.6. Some game servers quite literally require access to tens or hundreds of gigabytes of game data, in addition to support from various login and database servers. It's possible to do the leg work to make all of this available to the community but it's not trivial, and it wouldn't be "no cost to the publisher".