> What worse combination of technology can you have than being on Sprint’s network and CDMA?

You can just stack even more shit on the shit: it's branded as Google Fi and requires a modified firmware and app to hand off the calling layer between Sprint or T-Mobile.

(EDIT: The shit I'm referring to are carrier application/backdoors like this, without them the phone will not work on network: https://gist.github.com/thestinger/171b5ffdc54a50ee44497028a... )

Also note, nothing like that is required for a phone on any other US carrier, just Fi and Sprint are special.