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.
Not a problem at all. One atom has many electrons. Electron 'spin' has been used as a memory in the past. So, the lower limit actually goes lower than the atomic level. 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 don't care one bit if poor countries can't keep up with the cost to make a reliable network. If only first world countries can afford to make nodes, and those nodes enable a successful cryptocurrency network, I just don't care that Zimbabwei is left out of participation. Bitcoin is not here for the purpose of advancing socialism. I don't like a network designed so that it will run on 'shit' hardware for the purpose of assuring everyone can participate. It is not an important aspect of cryptocurrency that we assure all the downtrodden can have an equal chance to contribute to the network.