There's not a database of location data that all garage's can access. It's mainly about making it so that car manufacturers can't design car computers in a way

There's not a database of location data that all garage's can access. It's mainly about making it so that car manufacturers can't design car computers in a way that in a way that impedes independent shops from doing repairs without paying the manufacturers for access (think like custom data access protocols, or obfuscation that's only readable after paying Honda a monthly massive fee). This is the battle that farmers are fighting against john deere. Actually, if the data is only accessible to a few authorized shops, that's when the data is especially likely to be sold. Data is really only valuable in aggregate - if more shops can service cars, then each shop really gets less access to aggregated car data. More choice means less centralization of the data which means it's more difficult to collect enough data for it to be sold. I think the car manufacturers are the ones who are hoping to monetize the data, and that's why they're trying to restrict access.