DRM is a very modern concept. We originally made electronic solutions to mechanical problems because electronics allows for much more complex and nuanced response to input conditions, as well as the physical advantages of size and complexity.
Some systems are better as simple mechanical devices, but I'd put that number at a very, very low percentage.
Take your washer, dryer, dishwasher, or oven. These things can be purely mechanical, and are generally incredibly reliable when they are mechanical. In modern times, we've computerized these things for very dubious reasons mainly down to user tracking and enforced obsolescence. But adding network connectivity can be genuinely useful. Get a notification when your laundry or dishes are done. Automatically turn off the oven if you forget to when you leave the house. Track the runtime of your dishwasher and get notified when you need to clean the filter.
People would use features like that if it were possible to do so without a proprietary app that barely works, but demands your email and phone number and access to your microphone and camera. Or mandatory firmware updates that slowly degrade performance until you buy a new one.
The number of problems that can be solved mechanically and for which electronics cannot provide any extra value for the user is almost certainly very close to zero.