There are many ways to intercept SMS such as having a corrupt person who works for your carrier. This place got hacked too:

https://urgentcomm.com/2021/10/07/syniverse-quietly-admits-i...

Also what fraction of people are going to let their phone number lapse over the next 20 years? If my goal is not "target somebody in particular" but "cultivate false identities" the range for mischief is greater.