It’s happening, the Juniper Archer is now offered as Android (the raw Open-Source version though) and the Trimble has a bunch including the latest Nomad DC. The problem is they have old versions of Android generally and the best software has not yet migrated (Terrasync, FieldGenius, SurvCE, ArcPad, etc…).
To be honest, I picked up a Blackview BV9500 recently as a field device and it is a tank with a 10,000 mAh battery and Android 9.