The police can get your phone location from an app, or you car registration, yet these systems are still pretty secure, certainly not hacked by "everybody".
It will happen, exactly because incidents like this one.
It's usually a clerical worker with access but pretty often a cop. Just limiting access to certain groups isn't sufficient. It also needs to be restricted by time and purpose, audited with harsh consequences. Something the current systems already are not, so I wouldn't expect this to be.
The fact that one unrighteous power exists is not a good argument for another one.
Real-time phone location tracking is probably the only one that is more difficult to get. Even then, there have been cases where officers have abused that. Really, the reason more criminals don't use it is that the targets tend to be more random so it's easier to track a stranger using an airtag or GPS tag.
And of course, there have already been some people showing that stuff like onstar can be hacked to remotely stop a vehicle, not just by the cops.
They are absolutely abused by black hat resellers of this access to a broader audience for profit, and I would bet a large sum of money that there is more than a few groups who have infiltrated these companies simply to retain the ability to query this data for their own (nefarious) means like kidnapping/ransom/blackmail.
https://krebsonsecurity.com/2018/05/tracking-firm-locationsm...
https://www.vice.com/en/article/gykgv9/securus-phone-trackin...
https://www.zdnet.com/article/us-cell-carriers-selling-acces...