I have every intention of raising my kids as far away from smartphones as possible, ideally until they're at least teenagers. My fiance and I have already discussed keeping the household as de-screened as possible, it's something we consider a lot.
It's interesting you'd suggest that an app developer would have a conflict of interest that other engineers might not. In my experience, engineers who work with mobile apps, especially ones in the social space, are way, _way_ more likely to understand and be wary about the dangers in overexposing kids to a life of feeds. Colloquially, we call this "seeing how the sausage gets made".