Main supply line

Had to go under my hose to cap all the lines for a bathroom remodel. After looking at everything there were some curious observations. My main line for the water ran straight by my bathroom and didn't tee into any needed supply for shower or sink. It went toward the kitchen and laundry room where also sits our water heater. Then a different line comes back up the house supplying the bathroom. I'm no plumber. I just get by. Why would you do this instead of just teeing of the main as it went by in the first place. Teach me guys.

Can a plumber take a second and respond to this question please

Does the main line go to a water softener first???

Or the meter

no sir just from the street at the meter and then straight under the house directly to the water heater and laundry room