I, for one, wouldn't support practicing social distancing every year to prevent the flu season. And this always has economic effects as well.

Well there's negative economic effects to the flu in any case.

There's a variety of relatively low cost preventable steps that would just help in general if people followed them (may or may not fit your definition of social distancing).

I'm thinking of stuff like

- Contactless payments

- Head nods instead of handshakes for greetings

- More remote work options (where applicable).

- Mask wearing on public transit or by people with lots of personal contact

You'd restrict an enormous amount of commerce.

Wearing a mask in public doesn't restrict any commerce

Social distancing restricts some, but even without any legal enforcement I wouldn't be surprised if people just don't want to be close to others like before anymore. And for perfectly acceptable reasons!

I don’t think so. People are very good at adapting once confronted with a situation.