this... is certainly not my experience. However, they're a large organisation so they're most likely schizophrenic.
[1] https://www.reddit.com/r/boogie2988/comments/4psg4x/i_was_ha...
Being able to verify a code sent to the mobile phone registered with the account is used as proof of identity for account recovery by basically everything online except banking.
They do periodically put out some interesting reading. If you want to look at it, their annual Data Breach Investigations Report are worth checking out:
http://www.verizonenterprise.com/verizon-insights-lab/dbir/
(prior year reports don't require registration and are still fairly applicable)