Why didn’t the sub-prime lenders convert ARM’s to a fixed rate to prevent so many foreclosures?

So, do you mean they would rather foreclose and then sell at a discount instead of taking lower payments?
Greed does not explain it. Where’s the benefit in foreclosing??
If they foreclose they have to sell the prop@ a discount and take a loss. If they convert to fixed rates they take a smaller profit over the long term, but it’s still a profit.