I've experienced a lot of the same. I think the main cause for this is that WhatsApp still just works for most everyone, especially non-technical people - it's

I've experienced a lot of the same. I think the main cause for this is that WhatsApp still just works for most everyone, especially non-technical people - it's still a great product with many features, there's no settings you need to change, it's very reliable, moving to a new phone is literally just entering your phone number and allowing access(no accounts), etc. Some people followed me to Signal but there really hasn't been a lot of interaction, and a few of them even moved back after the huge downtime it had right when the big news about the new policy broke.