The answer is because they actually have no contact with those homeowners.
Most interaction on the loan is being done by servicers who were hired to process payments, not the holder of the loan. It’s a fairly low margin business, 0.25% of the principal, and a lot of the profit is in things like late fees, etc.
They don’t negotiate because their skin is not in the game, and because it is more profitable for them not to negotiate.
Capitalism 101.