My phone plan costs $14/month and could power music indefinitely at high speeds. Notably, it's something I already have and already pay for.
$300 more for a new stereo is still a lot to many people. Plus, if I buy beater cars but put a nice stereo in them I'm at risk of theft. And I have to pay install fees again if I buy my next beater.
This just further illustrates OP's point, of how very limited this market segment must be
The buyers of this product are people who:
- spend enough time in their car to want streaming audio
- spend money on phone and internet
- have a desire to improve their car to have streaming audio
- but not enough to replace the car
- and also not enough to replace the stereo
- but definitely enough to pay money to add it
- and are willing to remove the item they are paying for every time they leave the car to prevent its attractiveness to thieves
