Something I have never understood

A familiar email from the City of Minneapolis:  "Your regular collection day is Friday, however collection will be delayed one day due to the Labor Day holiday. Please remember to place your garbage, organics and recycling carts and up to two large items at the alley or curb line by 6 a.m. on Saturday."

How does that work, exactly? Presumably, people whose collection day is usually Monday will have their garbage picked up on Tuesday instead. Tuesday moves to Wednesday, and so on. But next week everybody's collection days return to normal. How??? How do they catch up? Why doesn't every holiday permanently shift my garbage service one day forward until eventually it works its way back to Friday?