As of 2016, how easy is it for someone who's not super technical to buy an Android phone without carrier branding that works well on Verizon or Sprint? Even if hardcore users of Slashdot have a lot of time to learn to do their own research, our non-technical friends and family may not.
As of March 2016, I brought a Nexus 6p to the Verizon company store and told them to transfer my phone number to it. They knew to look up the ESN/IMEI, poke it into a Verizon support website (on their own support tablet) to validate that it's compatible with their network, go get a nano-sim and put it into the phone, and transfer the account and phone number to it. Half an hour, no drama.
I didn't have to know, do, or tell them anything. I am a super technical guy, so I was watching like a hawk, ready to manspain anything they didn't get right, but it wasn't necessary.
It can work, if you get someone competent at the support site. Such a thing isn't guaranteed, but it's not impossible either.