Although quite off-topic, it's a pleasure to read your post and get inspiration to think more
This "easy money" concept, I'm still confusing. What is exactly "easy"?
A cook in kitchen cooking hard to make 20$/hour
A fund manager sitting in his office to make 400$/hour
A banker get 400000000$ loan from FED with 0 interest
An early bitcoin miner mined 25000 BTC
Which is easier?
How could you decide the money supply is excess?
And, why economy can't expand at 10% or even 200% per year, what is the factor that limit it? It's decided by number of people? Technology? Human nature?
Easy money is most closely represented by the 3rd item you listed. It's almost impossible to lose with a 0% rate, as you can use it for even highly conservative investments that might return 2% and be nearly guaranteed profit. Gov't takes all the risk and banks keep all the profit.
It's almost impossible to determine when there's excess in a modern economy of sufficient size. There are so many variables and changes take a long time to propagate through an economy. By the time the metrics used to observe an economy and decide how to manage it finally produce recognizable results, there are major distortions. That makes any actions taken more likely to cause harm and further disruption than correct any imbalances in the first place.
In order to truly be able to centrally manage an economy, massive amounts of data must be collected, increasing complexity and potential for errors. The task becomes herculean while allowing the system to manage itself would result in the distortions and imbalances resolving themselves over time.
There are
many factors that influence growth rates. Yes, the human aspect among others. Raw resource availability, energy production, global competition, population growth, infrastructure development, etc...