To refine inetknght's point. Assuming people are perfect economically rational actors we can also assume they have made the comparative advantage computation an

To refine inetknght's point. Assuming people are perfect economically rational actors we can also assume they have made the comparative advantage computation and found that it is economically better for them to do their own repairs. I also think you have the causal relationship backwards. Having an advance society of experts leads to less people doing everything on their own and doing their own repairs.