Re: Better than average returns??
What is the scenario where you think it will be of use? Any phone you buy will be able to use GPS from the US, Russia, China and the EU.
You answered your own question, all sat nav system's accuracy depends on the number of satellites it can see at any given time the more the better.
It looks like the industry is trying to make self-driving cars the next tech unicorn, I can tell you for free that reducing the positional error for that gig by even 10% is a big deal, and I am sure that there are thousands of existing uses for any GPS style system that would benefit from another ~30 satellites no matter who owns them.
And that's before we get to the real reason why these systems are built in the first place, modern military tactics and kit all revolve around precise positioning.
At this point having your own geolocation system for you forces is pretty much a requirement to be considered a tier 1 threat.