Not really. DRM usage has nothing to do with (honest) business cases. They are all crooked or Lysenkoist in nature (i.e. based on completely wrong / ignorant reasoning).
Also, I think you are mixing up DRM with security. DRM is the opposite of it. DRM can employ encryption, but its purpose is not to secure your system, but to police you, and because of that it actually compromises your security.
> apps and games increasingly rely on server backends to work properly.
Many multiplayer games surely do. That's why it's good then the server is open source. This way it indeed can be preserved. Otherwise, it will be lost as soon as the servers will go bust. Another option is to provide the server component with the game, to allow running it as server instance. Lot's of older games did that, allowing running LAN / WAN multiplayer without using dedicated servers. It's less common these days. Either developers cut corners with implementing it, or server components got too heavy, not sure.
Making single-player games rely on some remote services as a hard requirement is a very poor taste. Same if they have multiplayer component. It should be optional and single-player part should function without it.