This means no sales, no themed merchandise, no decorations. December 25 and most other day are treated just like any other day for all stores malls, restaurants, ect.
You’d still get non religious holiday events like mothers days, or independence days.
What whould change?
They’d loose loads of sales. I wouldn’t mind, as I don’t ‘celebrate’ those days anyway, but economically it would be bad for loads of stores and every company that is making or other way involved in all that junk.
It’s more about commerce then religion anyway.