Which is fine, as long as you don't mind being outcompeted and replaced by a system that is able to phase out stable boys.

You nailed it - statist democracy is having control over vast amounts of weapons, and forcing your way into the wallet of your neighbour, rather than competing and providing value to others.

Right, but the lesson is that we ought to look after the stable boy, not that the invention of cars was a bad idea.

Yeah which is why it's stated as a problem to be solved, not some immutable fact of life. The issue is that we've seen incredibly little progress in this area. There have been studies on the British coal mines that shuttered under Thatcher - the areas are still not back to the level of employment they had before the mines were shut. It's fine to say that shuttering those mines was a good thing - it probably was. It's also factual to say that those who felt the negative effects didn't benefit from the advantages of government policy, and ina human sense beyond employment numbers it means a lot of those people never worked again.

The crucial side-effect of most productivity-increasing inventions is marginalization of most of the work force (barring the few lucky ones - the SV engineers in the case of XXI century), destruction of communities and concentration of wealth and power in fewer hands. The luddites were definitely onto something. Wendell Bell explored these ideas in detail in his writing, if anyone is interested in learning more.

If you mean force others to take care of the stable boy, then no, it can not be moral.

What is moral and also efficient and kind is not standing in the way of him finding another occupation - to remove all regulation that hinders someone from providing value