Did your system getting better the more money you spent or more experience you gained?

I managed to get worse sound several times I added and tried new components. 

Sometimes, if it ain't broken....

The better the sound, the harder it is to improve it, easier to go sideways/backwards - for me. Still learning.

My thoughts always getting better, because I win more money and lose less as I age, but the rest of my system, while still in good "repair", cannot say is getting any better.

Both. I have, in the very beginning tried to minimize cost and maximize effort (gaining experience) and found I wasted more money by trying to save money… I would try going low cost and just ended up buying three intermediate components and the final one. I definitely never invest less than 2x or more on each upgraded component… I have learned that is a great way to be very disappointed. 
 

However any purchase that was not hugely researched and considered in the context of my system has not been as effective either. So, you really need both to build better and better cost effective systems.

I suspect how much time you have / money you make strongly enters the picture here as well.

I've been careful not to outspend my knowledge base.

It is both. It took me some money to determine what I like / trying to achieve. Then through reading, listening, think I had to spend less to get close to my goal.