Depends how much they can be bothered to run another client.
Here I run an ejabberd server so we are doing XMPP. On my PC I run MirandaNG which is a cool desktop client, my partner runs pidgin on her desktop and Yaxim on her phone. There are other clients, and you can go federation to connect worldwide if you want.
Main problem with all of these is the client. Once upon a time I could do XMPP, Skype, Twitter, Yahoo, Quakenet, etc., all from this one client, so there was no problem just having it backgrounding in the task tray and anyone could contact me at any time. Now, none of those work except for XMPP because they've all decided to take control of the users, so to do the same now I'd need a separate client for each, and those would probably be browser-based and essentially drag my computer to its knees just so I can be available. Fuck that. I will fire up Skype if someone texts me and says they want to chat, which isn't conducive to ad-hoc chatting which these apps and protocols is supposed to be about.
So the tl;dr is either the people you contact would need to be similarly into none of the popular stuff, or they would need to put up with yet another app running that won't be doing anything most of the time.