Perhaps it is, as cameras require looming and looming requires removing trim and finicking around which is expensive in man hours. Especially if literally every car that comes in is different.
Also fat looms the length of a car can still cost hundreds of dollars said and done.
Cost of installation is greatly reduced if all you need to do is line it up and rivet it on and there is no need to customise the power system to different cars (ie 12V, 24V) and loom layouts (ie old looms are crappy, hard to get apart for splicing, wires are old and might break during retrofit, some cars have +ive chassis)
Also fat looms the length of a car can still cost hundreds of dollars said and done.
Cost of installation is greatly reduced if all you need to do is line it up and rivet it on and there is no need to customise the power system to different cars (ie 12V, 24V) and loom layouts (ie old looms are crappy, hard to get apart for splicing, wires are old and might break during retrofit, some cars have +ive chassis)