Government bonds yield 3-4%. I don't think they ever calculated with a margin of just 4%. It's true that liquidity has dried up to some degree and companies have alternatives what to do with their money, but it's not like they though they'd yield only 3% by hiring more people.
yields dropped almost 1 point after depositor bailouts for SVB. the running belief is that the fed will slow down in response to fixed-income positions held by banks.
