There are things much more important than humanity's 'total productive output', which is anyway not guaranteed to
ever be managed and distributed in a better way. Human beings are not economic production units. The economy is a means and not an end.
Technologists are always hyperfocused on economic activity and insist that any problems technology creates will be solved by more technology. Well, all we appear to be doing is building an ever more complex and fragile civilization full of increasingly unhappy people racing towards Armageddon. What will trigger the ultimate systems collapse? I don't know, but I would be shocked if there isn't one within the next two centuries.
Yes, we probably would be better off without cars. Communities would be stronger, more tightly-knit. Urban sprawl would dramatically decrease. There'd be more multi-family housing. We would have spewed jillions of tons fewer of CO2 and other pollutants into the air (electric cars do not solve underlying environmental issues - they just shift them around to battery production and disposal and power generation.) One of the biggest causes of accidental death would be eradicated.
Instead of developing ICE/electric engines and understanding the best way to fit them into human society, we unleashed them willy-nilly and caused untold death, devastation, and misery. Such is the story of many if not most subsequent technological 'innovations'. (Yes, I have a car - two, even.)
Even now the 'ideal' Hacker News poster is hard at work at enriching fabulously wealthy companies intent on destroying privacy forever and creating dopamine addictions. We all say it's inevitable. But it's not. Every step of the way, it was individuals making decisions that led us to where we are now. We could have stopped it and we still can.
Or we can bury our heads in the sand.