Apple seems to have figured out a compromise.
There is an icon for turning off data to a radio (wifi or Bluetooth, for example), and an entirely different icon for if the radio is completely off.
If you have an iPhone, you can see this by turning off wifi and also your cellular connection. The wifi icon will change from color to black-on-white, while the cellular icon will change from color to white-on-black. This indicates that the wifi connection can still be used for things like AirDrop, but the cellular connection is off.
That's better than nothing, but my response to your post was to try it on my phone and then mutter to myself "okay, I guess"
I don't think most iPhone users browse HN to glean hints about the meaning of such opaque affordances, I had no idea that was what was happening when I turned off WiFi. I just figured it was actually off.
There are two issues with this implementation: 1. It's not privacy first. Toggling bluetooth should turn off everything. 2. It eats up battery/system-resources for a functionality that I don't want, causing me to have less control over my purchased device.