Having been close at hand watching her learn computer protocols, it isn't mental laziness. It's that the past is a foreign country and people do things differently there. Older people are from the past, and they just haven't been exposed to many more recent customs in circumstances that make them intuitively learnable. (Real example: how windows overlay each other on the computer screen; where the borders are and what the shapes mean. It seems so intuitive, but that's only because you already know it. If you don't already know, it's baffling. And if you do already know, it's because you learned it in Windows 3.1, back when it was simple enough to grasp.)

Also, older people's brains are full: with the policies and procedures of the past that younger people have no need to know. I've noticed this in myself, and not long ago made a list.