Sure, but pricing was the main driver. There doesn’t seem to be readily available historical pricing data but even as late as 2018 the price of SMS in Europe seemed to be €0.07-0.11 . Which means it was even more expensive back in the early 2010s when WhatsApp and others were beginning to take off. For the US the price per message is and has been $0. I think the extra features were ultimately just a bonus when compared to being able to send messages for free. The fact the US still hasn’t switched is proof enough that it being a better experience is not enough to compel people to change off of the default. Money is a huge motivator.