That’s not entirely true. The high end of aftermarket covers are electric, require the semi permanent installation of rails, wires, and the box, and are fairly cumbersome to remove. They’re not permanent in that they can be removed, but practically no one does this. Rivian’s truck has one built in as well. Most legacy manufacturers leave this to dealers to do as it’s an easy high profit accessory for them to upsell.
Just one of the many steps along the road to perfection: counterstrike.