they have a flip phone, so SMS isn't an option, but those people are so few that it doesn't affect the masses.
Huh? Every flip phone and service I've had in the 90s and early 2000s had SMS texting.
That was definitely not my experience. I've had cell service continuously since 1992 and did not get access to texting until more like 2002 and never sent or received a text until I would guess after 2006. But I had email on my phone before that and talked with loads of people because it was common in business then, because of Blackberry devices, to have email on the phones. ANd because texting was costly and rarely available, they had Blackberry messenger instead of texting on the devices. We didn't use it, but it was there.
Not my own experience. Texting was big for me and my circle back then, regardless of your experience. Besides the point though... Being a flip phone had nothing to do with SMS.