Without demand, there is no supply. In highly unequal societies there is no motivation to improve production efficiency--rather the opposite.
An economics professor of mine put it as "markets are created by demand, not supply." That was nearly 20 years ago, but it's really stuck with me.
As the linked article notes, the precursors for technological innovations were present in many places, but many of those places lacked one or more components of demand flow to finance the required innovation. Only after demand for industrial innovation is present do gaps in the supply chain come into play.
They also invented gunpowder and paper money.
They were basically an early modern civilisation, when Europe was still in the middle ages.
What do you know about inequality during the Song dynasty?
In many ways pre-industrial economy was a zero sum game for someone to be rich and afford to have enough capital to invest into developing industrial production somebody had to be poor. This mean that 90%+ of all people in China and in every other relatively large country lived in extreme poverty.
European colonial powers were simply the first to outsource this dynamic into other continents. While most people in Europe did not directly benefit from native or African slaves in the Americas the transfer of wealth allowed them to import grain and other products from abroad which simultaneously freed up enough labor to develop mining and other industries and increased the purchasing power enough to create significant demand for manufactured goods.
No reforms in China or any ancient empire could have achieved this as long as 90% of their populations were confined to permanently remaining subsistence farmers. Also the Song created paper money because they did not have enough gold and silver it didn’t really offer any benefits besides that and had significant risks. Every attempt to institute paper money, not directly tied to gold or silver prior to the 20th century failed.
Is there any evidence to support this? I remember reading that exploitive practices like slavery added very little to Europe's GDP. There seems to be processes - like advancing textile production and coal mining technology and metallurgy - that began long before the age of colonialism, and thus would likely have continued even in the absence of the slave trade.
Portugal and Spain had huge colonial empires, but that did not drive any industrialization or really long term wealth explosion like the capitalism and the industrial revolution did.
Paper money was certainly adopted. There was a class of administrators who could see the advantages, and so there was demand.
In Britain the demand for coal was independent of social equality. In the sense that everybody needed it to stay alive, especially during the winter.