The story isn't that brick and mortar hobby shops will disappear entirely, just that they will be a lot further apart and lots fewer of them overall. That has been the trend since the birth of the internet. And it will continue. Model train sales have slowly declined as well, especially O gauge. While there is some new blood coming into O gauge it is not enough to change the pattern. HO has some advantages that may sustain it for a long time. But, really, why fret over it; things change. And it will still be there for most of our lifetimes.
The same thing has been happening in the world of RC aircraft. Fewer people flying gas or glow engine planes. Hobby shops closing. But the introduction of great electrics and drones has breathed new life into that hobby.
