One time I had TomTom accidentally switch itself on in my bag on the floor, set to Homer Simpson's voice and trying to redirect me to home.
As I got further and further away the "turn left here" and "turn right here" directions got more and more frequent, until eventually he just started repeating "turn around where possible" until I was able to find somewhere reasonable to stop and turn it off.
Cost, I would imagine. It's there. It's working for most people. The "only people complaining" are those who want to take what you have to offer and stop you from getting advertising revenue for seeing it.
Your argument, whilst full of technical merit and other benefits which you have not mentioned, is perhaps not persuasive enough to those who control the purse strings.