Note: MVPs are other players, not Blizzard staff. MVPs do not speak for Blizzard or represent Blizzard.
At the moment, Blizzard has not publicly commented that it is even an “issue”, much less mentioned changing it. It is technically working as designed.
Previously the Mobile Authenticator only needed a compatible device and a one time internet connection to download, set up, and synch it.
There was also a separate optional SMS Protect service that sent you notifications of password changes, email changes, etc. Blizzard’s system has never accepted numbers flagged as VOIP or pre-paid. That includes Cricket. That was fine when it was only needed for an optional SMS service.
In the past 6 months or so, the additional phone number requirement was added as part of the Mobile Auth set up. So now it prevents anyone who does not have a “properly” flagged phone number from setting up the ONLY Authenticator option available. You see, they also stopped selling the physical keychain one…
Reducing availability of security measures seems to be backwards.