One chestnut from my history in lottery game development:
While our security staff was incredibly tight and did a generally good job, oftentimes levels of paranoia were off the charts.
Once they went around hot gluing shut all of the “unnecessary” USB ports in our PCs under the premise of mitigating data theft via thumb drive, while ignoring that we were all Internet-connected and VPNs are a thing, also that every machine had a RW optical drive.
Through a low tech social engineering attack referred to as SIM Jacking, an attacker can have your number moved to their SIM card, redirecting all SMS 2FA codes effectively making the whole thing useless as a security measure. Despite this, companies still implement it out of both laziness and to collect phone numbers (which is often why SMS MFA is forced)
SMS 2FA is used because it’s better than nothing and it works for 98% of people. Not many people have Google Authenticator, let alone other varieties.
The major weak link in security is people, not technology. People can be convinced to give up the 2FA code regardless of whether it’s a text or code in an Authenticator app.