We could see IG credit spreads in the 60s, something many haven't seen in their career. This is due to corporate bond scarcity, not improving fundamentals. The government is borrowing much more than the corporate sector. Half of US debt is private, half government; 10 years ago it was 2/3 private, 1/3 government.
You have to go back to the 1960s (guns and butter, Vietnam War) to find a similar dynamic. That's also when spreads were really tight.