I'm surprised that the GCC doesn't add some autodetection mechanism in it.
As 'hubicka' mentions in another comment, GCC does have "multi-versioning" capability, but it doesn't use it by default. Instead, one needs to mark individual functions with GCC specific attributes, asking for versions with different capabilities to be created: https://lwn.net/Articles/691932/. This isn't necessarily a bad approach, but the fact that it seems be used rarely makes me wonder if some other more default approach that works with unmodified code might be an improvement.
This leads to issues like you have on Mac: When using safari, the lower consumption is super low. With Chrome you don't get nearly the runtime (when playing video or listing to music).