Heavy SMS usage predates iMessage in the US. But iMessage was presumably a big contributor to making unlimited SMS messages the norm on most phone plans. In any case, there was just never a big incentive in the US to use anything other than iMessage when available and fall back to SMS otherwise. And without that incentive "no one" (who isn't texting people overseas) bothers to use different apps.
Oh this is true here too. SMS usage was huge pre-WhatsApp.
What happened was that the networks were capitalising on that. SMS was historically quite expensive so it became a big cash cow. SMS bits must have been made of gold because they were hundreds of times more expensive than other bits.
WhatsApp completely killed SMS usage here however. Leading to some carriers wanting to charge extra for WhatsApp usage to recuperate some of the 'lost' revenue. This sparked a big discussion about net neutrality which was then enshrined in EU law, so the discussion was finished. By this time, SMS became practically free but it was too late.
Interesting. It looks like WhatsApp predated iMessage in the US but it never really took off. Maybe US text bundles were more consumer-friendly in the US? Though I don't really remember it that way. (I didn't do a lot of texting though and mostly expensed the handful of work-related texting I did do; friends didn't really text at that time.)
