What kind of automation would make it easier to live in a small town? Do you mean a post-scarcity/jobless society?

Just having more online services like future-Amazon seems like money would leave the economy and destroy the town faster than building a Walmart does.

I'm not picturing post-scarcity or a hyper centralized form of automation. It's a possible path for automation to reach a point where it becomes feasible to allow semi-skilled folks in suburban or rural areas to run a farm, manufacturing plant, energy, mining or foresting outfit of their own for low startup and maintenance costs. Especially if human-level AI and human-level dextrous robotics does not exist yet.

Laborers would have a role to play with exoskeletons, being the eyes on the ground, and directing the robotic labor. Technicians would maintain the systems, and managers would organize logistics and resources. And as long as there is industry, there will be all the other types of supplementary businesses and jobs that come with a town.

The first problem is that zoning and noise complaints won't let you run a factory in a suburb (but maybe in an industrial district).

The second problem is that globalization and efficiency might mean there is nothing for the factory to do that anyone wants to pay for.

How many people are flocking to cities out of economic necessity, rather than desire?

When people are young, they may be a fair share of desire into moving to a city; but when they "grow up", most of them would like to get out of there and they only stay there because of the job.

When I say "most", I am not kidding. A few studies tell that something between 70% and 80% of people living in Paris would like to move away! That's huge.