I cannot imagine people being excited that they need to go physical store and deal with a staff there to get their fancy new toy.
I find it surprising that this is less common than it was in the past, and that people are more willing to put up with something that’s a subpar fit for them. One tech example that would benefit from custom fit are in-ear headphones. It would make sure that product is a perfect fit for every customer every time, rather than roughly every single customer having to put up with a suboptimal fit and poor comfort.
Older people today have been using computers since they were in their teens or twenties. Conversely, I know a 20-something woman who can't understand why her iMessages quit working when she switched to an Android phone, despite explaining it to her multiple times.
As you note, they also have more money.