Backup camera
 

Any one know of a way to turn on the backup camera in drive on a 18 F-150? Would be nice to check trailer.

It may not be impossible to set up,,,,,,,,,,,,,,,,,but the newer vehicles with sophisticated electronics monitor everything that is going on and when the power requirements change for some reason a module watching the system will shut down for "Self Preservation" .That always has to be considered when you start altering things .

Your prediction could come to pass, and I didn't say I thought live drive time camera/s were a bad thing. (for most)
There's no current restrictions to add full time viewing equipment, at least in this state I know of...
DVD movie screens can not be viewable by the driver, single ear listening device use only so not to limit sounding conditions while driving. All for safety reasons.
In reality, its not much different than having or using complex audio equipment or watching a Google moving map finding your way around. Camera views can keep a watchful eye on loads and conditions, no doubt.
But,, at the manufacturer level, they may never want the liability of an operator rolling down the highway cycling between camera views watching a screen and not the path the trucks making.
For now,, like cell phone usage while driving 'is' a distraction by law and has the potential to cause loss. With panel live GPS mapping, audio distractions, and/or the combination of, could be they don't want to add to the mix with live camera imaging.

I'm a pilot, and I can tell you with I/P glass panel moving maps, weather data, in flight data at your finger tips, is huge as far as position/situational awareness. Safety,,absolutely, but at a price,...
Screen viewing aids in flying the airplane from inside the cockpit, meaning its potential for stealing valuable or critical time looking at the panels and not out the front screen has created devastating problems of its own... Pretty important.....
Could be at a point that the manufactures and law makers will allow for the features, could be that a line in the sand is drawn as far as allowances. If camera viewing is,, then the potential argument for cell phone/text use and alike could be... Liability most likely being the deciding factor...