So in order to drive the yield curve negative, wouldn't that mean a massive increase in the amount of money going into bonds? So that they no longer have to incentivize people to buy bonds, but can actually make them pay to take them? And if there is such a massive increase in bond volume, where is that money coming from?
The fed had for years engaged in massive bond buying (QE). That has reduced supply of government paper and therefore reduced yields on the bonds.
So not a massive increase in demand, but a massive drop in supply?
You are confusing an inverted yield curve with negative interest rates.