This directly mirrors how the OS manages suspended/background apps, but with the critical difference that the OS specially treats apps which are registered for different background services, like background audio playback, avoiding eviction for things like this which are effectively under active use, even when they are not on-screen.

The solution, I'd argue, is for Apple (and the web working groups, in general) to bring the same sorts of OS design concerns to browsers—in this case, richer interfaces for more intelligent handling of background tasks by both the runtime and the tasks, themselves.