We have these things we carry around with us, called "phones"; they are actually general-purpose computing devices and making (what we still call) phone calls is a small part of their purpose. And to an increasing extent these can fulfill almost all our computing needs.
So, fast-forward a couple of decades, assuming no huge technological shifts[1]. Everyone is used to having one of these things that they carry around in their pocket, and scarcely anyone really needs any other general-purpose computing device. We still call them "phones" because we always did -- so now this is the usual term for a general-purpose computing device. And, yeah, there are some people who, because of their unusual needs, have a bigger more powerful one. Well, what are you going to call something like a phone but sized to sit on your desk while you work? Obviously it's a desktop phone, right? And somewhere out there In The Cloud there are whole farms of server phones :-).
And there will be conversations like the ones we[2] now have about how "computer" used to mean a human being who did calculations. "Hey, did you ever look up where the word 'phone' actually comes from? It turns out that back in the 20th century they mostly used them for talking to one another, and it comes from some Greek thing meaning 'sound at a distance'. Weird, huh?"
[1] That's a pretty big assumption, of course.
[2] For sufficiently small values of "we".