So, it's sort of like bundled mortgage securities, where you take some bad loans and mix them together to get a "less risky" loan, since the chance of them all defaulting at once is less than the chance of all but one defaulting.

Presumably, since banks (by definition, an intermediary) are involved, those are then recursively repackaged until they have an A+ rating, or some such nonsense, right? Also, I'm guessing there's no rule that says you can't intermingle these things across separate "independent" securities, even if the two securities end up containing fractions of the same underlying bad loans?

Clearly, like with housing, there's no chance of correlated defaults in a bucket of bad business loans that's structured this way!

In case you didn't quite catch the sarcasm, replace "housing loans" with "unregulated securities" and note that my description switches from describing the 2008 financial crisis to describing the Great Depression, or replace it with "bucket shops" (which would sell you buckets of intermingled stocks) and it would describe every US financial crisis of the 1800s.

How is this inconsistent with what I said? I was just making the point that the reason for the rise of private credit is that banks are less willing / able to lend, particularly to riskier borrowers, as a result of post-2008 banking regulations. So private lenders have stepped in to fill that gap.