So then if everything goes to ADS-B and GPS, doesn't that create a potential single-point-of-failure scenario, as isn't the data that ADS-B sends out itself der

So then if everything goes to ADS-B and GPS, doesn't that create a potential single-point-of-failure scenario, as isn't the data that ADS-B sends out itself derived from GPS? Having all navigation information come from a single source strikes me as about a good idea as the single AoA sensor on the 737MAX. I'd like to be wrong about this, but I'm not sure how I am. How am I potentially wrong about this?