seriously. Who had such a stupid idea, and who APPROVED it?
You're letting the perfect be the enemy of the good. Most of your "reasons" are easily avoided (srsly: "may force both parents to change phone, just to install that app, if it’s not compatible with the ones they already have"?? So maybe...they buy a solution that works for their phones? And how many apps are phone-specific these days, anyway??).
This isn't a *required* solution. It's not like every kid in a car seat is going to die if any of the failure modes you list come to pass. In fact, what you're describing is ANY such system: by your logic, smoke detectors are stupid and bad because batteries can run out, or electronics can fail. Or any other technology that's imperfect (as, indeed, all are).
Sorry, your rant is illogical and harmful.