25 years ago when circuit feature size was 1 micron - we were saying the exact same thing. I really don't know how anyone is doing 14um. That seems totally impossible. But - whatever, they are doing it.
The problem arises when you reach the size of 1 atom.
I don't think memory capacity will continue to go down like the chart for the last 20 years. It will go down however. Now, memory is so fucking cheap it is shocking. I once paid $100 / Megabyte (RAM). Now when I buy 128GB flash for $30 I laugh my head off.
As for bandwidth - the arguments here are hard to accept.
Again, it comes down to where the user is from. While $30 might seem like a small amount in the US, it is a big amount in remote places in the world. It comes down to whether and by how much you want to restrict node usage. Do you want nodes only to be run by people in 1st world countries?
i think better solution for this could be cd or pendrive with the copy of ledger which can be released on yearly basis. So that the one who like to host own wallet can download remaining few blocks within few hours.
Nothing prevents you from selling one, but it will get outdated pretty quickly.