The only large group of people who still primarily use SMS to communicate person-to-person is Android users in the USA.
Every other country has settled on either Telegram, WeChat, WhatsApp or FB Messenger, or other niche apps. These apps work on both iOS and Android and often also Windows. I haven't sent an SMS in probably 12 years. I don't know anyone who has.
It's only in the US that iMessage is so prevalent that Android users have to use SMS, the only other way of messaging iOS devices. And the US is quickly becoming a de-facto iOS only country. It already has more than 50% market share, even 80% among young people.
With the US going (almost) full iMessage and the rest of the world having already settled on another app there simply no point to supporting SMS.
Jokes aside, I see SMS as a useless protocol; because it cannot be used for identification, and neither can anything be encrypted nor verified without another communication channel.
It's also not in the power of the end user to decide whether or not their number gets reassigned, blocked, or does work at all. Most US people seem to think that it's normal to have "one" number for years on end. For the rest of the world, it's not true.
For example: If I don't use my SIM card to make phone calls (which get billed) for 6 months, it's gone and reallocated to a different person.
Uh, I’m from Germany and had the same mobile number for over 20 years.
Even two years ago, I had to actually change a phone number because I couldn't transfer my number from one provider to their own reseller. O2 Scheißladen.
Huh, I guess I got lucky staying with Viag Interkom and then O2 (which was an automatic switch when O2 bought them) for so long, I only really switched providers in 2020 which was long after the EU regulation was in effect.