@nerd7473 @breadandcircuses my then-13 and 14 year old brothers built motor bikes without access to anything more than mechanics magazines, and this was before high school shop class.
I would imagine if we decide it's worth using our limited resources to build more cars instead of more trains and buses, we can indeed build cars!
Even engineer them. We don't need to go faster in cars, we need to reduce our dependency on them for a multitude of reasons every one knows.
So, as a society not beholden to stockholders, we could indeed continue to engineer and build, locally, the equipment our societies will need.
Check out the community in NW Missouri, USA designing and building equipment that can share a single power and operational unit, to do every task needed done in farming and building, maintaining roads etc.
We share ideas and plans and we build what we need with the resources we have (including tons and tons of repurposed resources) with less waste and more consensus in what gets built (it's a crime cars don't come with seats safe for children and small adults *built in*)
And we don't overbuild, and when we don't need to be building cars we are free to build other stuff (engineering your factories to be the absolute fastest and cheapest builder of sedans makes them too limited. Build fewer, slower, and make them easily repaired and modified.
Already a better world!