There are a number of tools called “steamworks emulators” that allow one to bypass this outright for many games. These are generally seen as piracy tools, but t

There are a number of tools called “steamworks emulators” that allow one to bypass this outright for many games. These are generally seen as piracy tools, but there’s no good reason you couldn’t use them when you wanted to play your purchased game collection without DRM. Be a bit careful when experimenting, though. You may run into problems syncing your cloud saves for some games if/when you go back to the official client.