iOS is getting close to being all the computer my grandparents could ever need. My mother as well. My father and I are both in tech and would run into too many hard (and fairly artificial) limitations pretty quickly.

I won't ever switch my primary computer to something that needs an optional accessory to hold the screen up. ipad may be magical, but there is plenty of wonder left in a device can open up and start typing on a real keyboard immediately. It's been many years since my primary computer has been a desktop, but I'm not willing to compromise on the permanently attached keyboard and freedom to decide what executes.

An iPad is already the only computer my parents own. They don't even have smart phones.

And that iPads + keyboard are significantly cheaper than MacBooks.

Cheaper yes. Significantly? Not so sure. Unlike iphone apple hasn't been selling the old ipad pro as a cheaper, more entry level product. The base price of ipad pro has gone up each time we've seen an updated one until now we're firmly in macbook price land once you get functional storage. The modifier-free macbook is a similar size to 12.9 inch ipad pro, but ipad is actually more once you get 256 gb of storage and the optional keyboard.