The idea is to force the companies to provide an end-of-life plan that leaves the game in a "reasonably playable state". Depending on the game the approach can differ. Releasing the binaries along with instructions for hosting dedicated servers is one approach (that some games already take). I was playing on a (pirated, but it was a long way ago and I was a child) Lineage 2 server way back in 2007 on my local ISP network, so even something like MMORPGs can be covered if it's included in the discussion at the design stage of the game.
But even if the backend is very complex and vendor-locked, releasing something like a set of Cloudformation templates and saying "you can only host this on AWS and it's going to be restrictively expensive but there you go" is also an option that would satisfy the requirements. It's still better then having nothing at all to dig at (although some fans still do reverse-engineer and spin up community servers even without having access to any of this).