is there a good reason why trailers do not have backup lights?

We have them wired to to trailer power.
Separate switches for the side lights and rear lights. We call them work lights but are used to back into dark areas.
We have to get out and flip both toggles before backing though, no cab switches for them.

 

My trailer has factory ditch/work lights that come on with the blinker.. Canadian made trailer.too..2 flood lights for left turn and 2 for right turn. 4 if 4 ways are on. I find them to be mostly use less. But I have a second 7 way plug with 1 circuit for backup/work lights.

 

There are wireless relays that come with a remote to turn on/off.