I don’t think long-term GDP measures are meaningful. What point is there in comparing an economy that produces horseshoes and wooden ships with one that has tr

I don’t think long-term GDP measures are meaningful. What point is there in comparing an economy that produces horseshoes and wooden ships with one that has trains and steamships? A pre-industrial economy can’t produce X% of an industrial economy, because it can’t produce large chunks of that economy at all. At best you can compare the parts of the economy that remain relatively unchanged - like food, or textiles, and use those as rough and incomplete proxies.