There are a lot of things our devices could do to give users insight into basic things like which apps use a lot of resources, but they don't and it's a colossal failure for everyone (users, people who make efficient apps, pressure on people who make inefficient apps).

iPhone's battery usage screen is a microstep in the right direction, but it doesn't go far enough since the user has to know it exists, then visit it regularly and mentally calculate if the app's energy consumption is proportional to the amount they use it.

Just consider how an app can get stuck in a 100% CPU loop on macOS (Discord/Spotify used to do this to me if they had any animations on screen) and there's literally zero indication to the user that it's happening and which app is responsible. Best they get is that the computer's fans turn on, if it has them.

One improvement would be for the app-switcher view on iOS/macOS to show you the app's battery impact and average memory consumption. Anything would be an improvement.