An interesting alternative to consider, is money that intentionally depreciates value at a fixed rate ("demurrage" [1]). In theory, this would incentivize lending at zero interest (assuming relative price stability for real goods, which is easier said than done).
This is exactly property of coins (gold, silver or copper). Even without debasement (like clippage) they were loosing value as they were worn out as a result normal usage. Money changers were exchanging worn out/damaged/clipped coins at current market value minus some comission.
Jesus apparently didn't appreciated that a Jew coming from say Alexandia or Gallile had been bringing a bunch of coins of different origin, issuance, often clipped or destroyed by use... Charging 4-8 percent (kolbon) for exchanging used and foreign coins into new shekels required by Temple wasn't excesive. It is on par on charges for foreign purchases by today's banks.
Temple services (purification, healing) were on the other hand prohibitively expensive while Jesus provided them for free...
Historically there were many Jewish people not happy about this happening in the temple. I doubt Jesus was the only one driving them away from time to time, they just kept coming back to the temple.
The rest of your post is just made up based on trying your best to interrupt things in the worst possible light it is not more reasonable than believing anything else.
It's not made up. It's just modernized. And he was 12 according to NIV