Never had a cell phone but I'm a millennial. The apartment complex I'm in, built in 2004, isn't even wired with land lines. Though it is wired for a fiber optic internet connection :-).
I'd imagine most of the young children unfamiliar with landlines will have this attitude if you try to explain a landline phone:
"So this land line phone thing. It's like a cell phone, but you can't move the unit and talk on it at the same time? Oh if you get a more expensive wireless setup? But then you can only go a few dozen yards from the base? And you can't text or IM or check Facebook or get email or take pictures or watch movies or browse the web? And the phone number is attached to the house and not the phone itself so I have to get a new number when I move? And I get charged extra for calling people not in my zip code? And it's like $10+/month? Who was ever dumb enough to buy that?"
Awesome! That's like trying to explain a VCR, Tape Deck, or Floppy Disk. Though my wife still has her walkman (her old ipod broke and she never moved the music to her iphone) and our daughter picked it up. That was amusing.
I don't necessarily mean "landline". We use VOIP through the cable provider since I used to work for them (ahh, that was nice -- full cable, fast internet, and phone for less than I pay for gas in my mazda 6 every month -- and I work from home).
The other advantage to having the home phone is that you can have phones in rooms without taking them around. Yes, they take up a little space, but I don't have to move chargers around.