Let me preface this with that my experience comes from Sweden in the 90s and 00s, and is a correct and truthful lived experience of my life. Seemingly, things were different were you lived, and that's fine, but that's not how it worked all across Europe, so at least we can agree on that :)

The initial claim of "WhatsApp happened at a time when, in Europe, you paid for SMS." maybe was true in parts of Europe, but clearly not everywhere. People were mostly using the Facebook chat (not Facebook Messenger/Chat) already before Whatsapp started being used, although Whatsapp in Sweden still isn't as popular as in other countries. In Spain, everyone uses Whatsapp, in Sweden, seemingly the people I talk to only have Whatsapp to communicate with me and others outside the country.

> Many people were not mostly texting free in 2009

Most people I knew definitively were mostly texting for free even before 2009, again, at least in Sweden.