Otherwise, it may be that the Fed reducing its budget sheet is irrelevant, or is a factor that is only exacerbating factors that were already at play, or even, perhaps, that short term yields exceeding long term yields actually causes recessions.
In capital markets, in order to justify taking risk, there has to be an accompanying return, otherwise people will not invest.
Inversion of the yield curve signals exactly that - returns are not enough to justify the risk, and that capital expenditures will go down, leading to lower returns, lower employment, and also a recession.
There is one key thing that very few people are talking about, however - the Fed basically controls the debt issuance, and has some (possibly even significant) ability to nudge the market in the direction it wants by buying/selling towards one end of the curve or the other.
This alone can effect the economy, but the Fed does not have a strong history here. But it's definitely possible, and I think we may experience that with the current Fed President, Jerome Powell.
[0] https://www.schwab.com/resource-center/insights/content/eye-...
[1] https://www.newyorkfed.org/research/capital_markets/ycfaq.ht...
[2] (PDF) https://www.dnb.no/seg-fundamental/fundamentalweb/getreport....
Edit: Missed the first question in your post. The Federal Reserve is essentially buying fewer Treasury Bonds when the bonds it currently holds matures. Instead of reinvesting the payoff + interest that it received for those bonds, it is now just taking that money and essentially keeping it out of circulation.
There are many other factors, but it should be noted that this is the longest time of a financial expansion (time since the last recession) in modern history. In the 70s and early 80s there were 4 recessions in a 12 year period.
No. When the Fed buys bonds it issues MONEY.