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?
Like what would happen if stores gave up possibly their most profitable period of the entire year? Christmas would go on via Etsy and eBay and such. It might slowly die as the years go on, but Christmas has a lot of momentum even if stores aren’t selling the gear.