I think the argument about SMS being insecure is very real but exaggerated. We send password reset with capability URLs through non encrypted mail. Sure, the channel is most likely encrypted but anyone at mail service providers could easily take over a massive amount of accounts. Although the user would notice at least.
Sure, there are tools to intercept SMS without the user noticing, but as a second factor an attacker still doesn't have access to other factors.
The successor RCS has the problem that users cannot reset the password. If you are compromised you need to urgently contact your ISP.