Thank you for sharing your experiences. I found the anecdote of Saxony particularly interesting, because I was doing the exact same thing when I realized that playing tall was actually getting a bigger return for my resources. I played on Very Hard and disliked blobbing in blatantly ahistorical manners for roleplay and aesthetic purposes, but during that Saxony campaign, I realized that with many recent changes to the game playing tall had become ridiculously powerful and started developing and optimizing my strategy to apply to competitive MPs.

Indeed, money leads to more money, both in capitalism and in EU4, and this is why spending your resources efficiently in the way that returns the most resources is extremely valuable. By gaining more resources quickly with efficient investment, you re-invest and continue gaining resources even more quickly, rinse and repeat, until you have an absurd amount of resources. This is also how millionaires become billionaires, applied on a real-world scale.