> and they'd have a car there in 5-10 minutes max
The introduction of low-cost options for Uber/Lyft were arguably as important a development as their original ride-hailing app ideas. Once the fleet was no longer constrained to professional drivers, and anybody with a spare hour or two (and a car) could go online, the size of the fleet exploded. That meant the likelihood of having a car near you - no matter where you are in a city - dramatically increased. Sure, call your local car service from home when you're heading to JFK and he'll be there in 10. How about when you're in the Village at 1am? How about Red Hook? Not to mention this allowed the service to be provided in cities all over the world which didn't previously have a car service at all.
> 10,000 highly-paid developers
Uber probably services more than 10,000x the number of rides than your car service did. I suppose you could try employing 10,000 "ladies with a phone" to handle that volume - but of course human dispatch quickly becomes unable to handle those kinds of volumes. Sorry, those developers are necessary for scale.
> and providing a marginally better level of service
Car-sharing with strangers was impossible before Uber/Lyft operated at scale. Share a car to work with some of your colleagues, who happen to live near you, sure. But to car pool anywhere at any time requires a huge fleet, and the technology to match riders who are taking the same route. That is an very difficult problem to solve, and yes it takes capable engineers. That car pooling allows fares which are probably around a third of what your car service charges. More improvements are on the way which should see short-medium trips of a comparable cost to public transport.
Not to mention providing this service in under-served and otherwise unprofitable areas, to minorities, at all times of day, all across the world. Plus of course a consistent name and brand, by far the biggest value-add ;)
Now integrate with other modes of transport - public transport, bikes, and yep even scooters. These companies are positioned to shape entire cities' transit systems (they already have, for better or for worse). They're not the same as your small car service, and they're not over-engineered. They're certainly not setting out every day worried about justifying their Silicon Valley existence.