Virtually all phones have acceleration sensors and can/could do short term inertial navigation in tunnels or areas with poor reception anytime they want. And do

Virtually all phones have acceleration sensors and can/could do short term inertial navigation in tunnels or areas with poor reception anytime they want. And don't forget that phones have many different ways of getting position information: bluetooth, wifi, cellular tower triangulation, etc, etc. I see no future world where in-car navigation could ever compete against a cell phone. For one, I replace my phone about every 2-3 years, whereas most cars have a far longer lifetime and none of the fossil burners have ever thought of having upgradability of the individual components as a selling point.