Even though the numbers in process node names keep going down, this no longer directly corresponds to line widths. For example, the largest difference between TSMC 20nm and 16nm is that the way the transistor is built was completely changed.

There are a couple of transitions like this left that buy real performance and density, even if the actual line widths stay as they are, so there likely will be a "3nm" process node. After that, who knows.

Agree it might be possible, but still, my point is that gains become smaller and smaller, more and more complex, and you still don't end up with transistors an order of magnitude smaller.