What's the problem with families? My local Uber-equivalent will have and provide child booster seats if requested (as did many but not all "pre-app" taxi service providers), and for infants there are also a bunch of solutions depending on their age; one of them (perhaps not the best, just anecdotal example) is the combo carriage+car seat, where I can put the "carriage wheels" in the trunk and put the baby in the car safely without even waking them up, crucially, it can be done in any car or taxi, and I've taken taxi rides with a baby this way.

It does require some planning (and some support from the service providers) but it's definitely a solvable issue, if the people would want to do that, then it can be arranged.