Recently I realized that our kids will never experience something called "bill paying." While they will certainly exchange their money for services, it will all happen by electronic funds transfer or some version of it. And your kids' kids won't know the word "checkbook."
You grandkids probably won't deal with the concept of a home phone number, since all numbers will go directly to individuals. And the fax machine has one foot in the grave, as most new printers allow you to scan to e-mail.
I'm hoping that "booting a computer" soon goes away. Someday it will seem funny that we had to wait minutes to fire up the old Personal Computer, which is another phrase that is already mostly dead. Now we just have computers. The personal part fell away.
Perhaps the word "television" will be gone soon too. You'll have a monitor that can access all forms of entertainment from the Internet, and network TV shows will be a small part of that. Television already sounds old timey.
Computer backup will cease being a spoken concept, except by engineers, as soon as all computers do it automatically over the Internet and on the fly. That's probably coming.
"Online" is a word that will fade away, once that becomes the only way anything gets done. It already sounds ridiculous to say you booked your airline tickets online, since that is generally understood.
What other concepts are going away?