I may not have all the facts, but I think it's fine for the black cabs to offer a luxury service that you need to pass a hard test to join. This is distinct from making it illegal for someone else to offer an inferior service at a discounted price.
On top of this, in central London it's pretty built up so SatNav doesn't always work in the canyons between buildings.
I'm not sure if there's actually a comprehensive source for bus lane data - if there is, it would be really useful for motorbike users too (who can generally use bus lanes).
Also, even if GPS signals are hard to get in London, navigation in a fixed city can be calculated in lots of different ways. Allowing for some regulatory limits, a company (or an experienced third-party) could scatter their own transmitters around the city as needed, figuring out which frequencies give the best accuracy.
The better informed the satnav, the less valuable that is.
Maybe in 2024.
Simpy by sheer logic the very act of using a navigation aid (phone, Sat Nav, map) must result in decreased attention to the mechanical process of driving.
I would challenge that safe navigation is a long solved problem.
Who solved it? How? How was it measured? When was it solved - 2013? 2004?