You measure by market cap. Acquisitions are paid in money, not subscribers.
Edit: Also wikipedia says that the AT&T stat includes "connected devices". If that really means they count all individual connected devices, thats a useless comparison. One customer can have multiple devices.
Edit: Also wikipedia says that the AT&T stat includes "connected devices". If that really means they count all individual connected devices, thats a useless comparison. One customer can have multiple devices.