If I recall correctly (I might be wrong, because this was 10+ years ago), but Apple did exactly this when the iPhone was first released. When the iPhone first came out, Apple released its XCode devtools for free, including an iOS emulator that you could use to test your iPhone app. But you had to pay a $99 USD per year "developer program" free in order to use the devtools to test the app on your physical device.
If Google is also blocking preventing you from loading your own software onto your own phone with adb unless you pay a free, then this would be a very important thing to call out explicitly.