In many countries SMS was either crazy expensive, unreliable, wall gardened to death (can't message people on other carriers...) and had no traction in the first place.
Then phone calls are also crazy expensive: I'm looking at the phone plans right now and the main focus is the data amount. Phone call options are either to only allow for super short conversations for a flat fee (less than 5min per call, for a 25% increase in the monthly plan) or 30 min to an hour of phone call for double to triple the price of the plans.
Moving to an alternative is just the normal course given these incentives, and that's what people did in droves (looking at Japan for instance)
Yes. This is the norm in the US.