I'm not actually suggesting using MMS. I just wanted to illustrate that we've had instant communication technology (even "rich" multi-media) long before Whatsapp etc. Why didn't the providers of that technology (telecom companies) become Meta?

The difference is that MMS/SMS is standardized and agnostic to the client interface. While WhatsApp is proprietary and monopolizes the client.

We could easily have had a "internet direct message" standard implementing most of WhatsApps features. (Wait... Isn't that SMTP?)

Maybe I'm just ignorant, but what does WhatsApp bring that let's say email++ does not have?