>people are less likely to hold corporate debt and instead hold cash. People are less likely to hold corporate debt because the corporation has less revenue to service its debt.
This omits part of the investing dynamic and is too simplistic of a conclusion for what's going on right now. There has been sky high investment grade issuance over the past two months and there doesn't seem to be a lack of demand for it. What changes is the price the market demands to hold any asset. There is always a price and that's why companies (cruise and airlines) that are in way worse shape than Uber have been able to raise money both in the debt and equity markets.
>if Uber were to try to sell bonds, the spread over, say, treasuries, would probably be above 8-10%.
> In other words, corporate debt isn't priced according to lowered rates.
These two statements are contradictory. Nothing exists in a vacuum but all else equal, if rates are lower, issuers are usually able to issue for lower all-in yields. Additionally, high yield is a much more idiosyncratic market with way less interest rate sensitivity and new issuance is almost always priced on yield; not spread.
> The only way the Fed would help would be if the Fed bought Uber's bonds, but that would require Uber to be investment grade, which would be laughable, or a "fallen angel", a company which was investment grade before the crisis but has since been downgraded.
The Fed has already helped Uber as well as other high yield companies through the various facilities it has announced. They are not directly affected by any of them but as with all central bank policies, it creates a reach for yield that flows all the way down.