ok, you want to know?
you can't build submarines in a poor country without directing vast assets from disparate sources into this project. that is not possible in your system. of course, an authoritarian government need not be maoist, and being authoritarian isn't enough, but why particularly maoism?
1. economic nationalism. Mao was a firm believer in that everything China had MUST be indigenous to the point of cutting off foreign trade. that means that the burden of achievement is on the native scientists and engineers alone, and there's no shortcuts.
Maoism had nothing to do with that. Russia too had the same policy in defense, as did USA, that they will manufacture all defence products in house. Until the recent mistral warship deal, Russia has never purchased anything (defense related) from abroad. Nothing unique to maoism.And by the way, China has purchased far more from abroad than the Soviet Union and the USA put together. (And so has India.)
2. command economics. This ensures that the scientists and engineers WILL get the resources they need, even if it starves other parts of the economy.
Command economics is not a prerequisite for succesfully building submarines, and is in fact a hindrance. The USA has the very opposite of command economics, and yet built better submarines than china. And the magic of free market economics is that it does this WITHOUT starving other parts of the economy, and in most cases, ADDING to the other parts of the economy.
3. large labor and capital pool. this means a bigger pool of savings to draw on without significantly negatively impacting living standards.
Large labor pool is NOT because of mao's ideals. That is dependent on the population of the country. China happened to be a big country, as is India. And this point has nothing in particular to do with submarines or nuclear weapons anyway.
4. experience in heavy industry. Many things in industry cannot be designed from the ground up but need preexisting knowledge and experience. China had this due to Mao's industrialization drive in the 50's with Soviet help.
Again, industrialisation is not due to maoism in particular. It may have been mao who started industrialisation in China because he was the head, but that does not mean it stems from maoist ideology. The industrial revolution happened much before mao or even karl marx was born. Capitalist countries are in general much more industrialised than the non capitalist countries. And china's industrialisation has only INCREASED after mao's regime ended, and mao's policies were wisely ditched.
5. military nationalism. This is the motivator. Many countries with the above have no motivation to build a nuke sub.
There are many, many countries which have military nationalism, even more than chinese (say north koreans). None of them have made a sub, or anywhere close to it. Countries like India, USA, France etc where military nationalism is almost non existent HAVE made subs. Countries like sweden where militarism is almost an ugly word, and recruitment ads only show the military doing humanitarian works, have produced fine combat planes and stealth frigates that China can't match in quality. So don't pretend that military nationalism is either a necessary or a sufficient condition for that.