HereForTheBeer: And for those that don't really need persistence of data from one session to the next, there shouldn't be much need for account verification through the publisher.
If all you need is a persistent data store, well there are ways to provide that without DRM.
In the simple case, the publisher can host their service but leave it open for anyone to sign up with (yes, this means they also shoulder the cost for pierats). It doesn't need to be tied to my ownership of a given title in my Steam / GOG library. There are many games that work this way, and I do consider them DRM-free. But if they're forcing me to go through accounts and services "just because", in a game that doesn't really need services (and maybe even provides a LAN option, again artificially restricted to LAN), I get frustrated. I'm pretty sure they do that intentionally because it is effectively DRM.
The other approach is to let the client or the hosted servers keep your data. E.g. community-run Q3 (and derivatives like Enemy Territory) are already tracking players and keeping data on the servers. In ET, each player has a unique id by which they're recognized. Client-side storage is another option, and can be made tamperproof through digital signatures. Obviously this is only good for data that is only needed when the client is connected.
Seriously though, if all they want to provide is a goddamn leaderboard, no, no, there is no need to check that I'm signed in to GOG and that I have the game in question in my library.
"Who is this player" can also be implemented thru signatures. Obviously some sort of repository hosting the public keys must be available. Even with millions of players that's going to be pretty small and read-mostly, thus easy to distribute. A little bit of latency with new sign-ins wouldn't generally hurt but even that can be optimized out by only syncing as unseen keys come up.
The problem is that game devs have zero incentive to take this route when even supposed DRM-free advocates are more than happy to sell their soul for multiplayer. So devs tie their product to your store account which is convenient for them and gives them DRM as a byproduct.
And then some DRM-free advocates praise the "good guys" that provide a "LAN" mode artificially restricted to a switched network or private address space. (It's still UDP over IP or TCP over IP under the hood and would work all the same even if there's a router or ten between the players)
Yugh I'm so disgusted :(