I still don't understand how SMS took off in the US. for a long time you had to pay to receive texts, which is madness.
given that undercurrent of expense, I'm still not sure why the US hasn't moved to whatsapp/signal/other. The only thing I can think of is that mobile data is even more expensive.
When you had to pay to receive SMS, WhatsApp didn't exist. Your only other options were more cumbersome things like email and AIM, which still required paying for a phone internet plan and having a capable phone.
given that undercurrent of expense, I'm still not sure why the US hasn't moved to whatsapp/signal/other. The only thing I can think of is that mobile data is even more expensive.