Comment by FireBeyond

That's a generous payment estimate. The actual numbers at the current 6.5% are that a $2700 30Y will be a $2450 50Y. It's not a 20% decrease in mortgage payments. It's more like 9%.

And uhhh, there's the small matter of "what you're putting in SPY" being rather offset by the $1M+ extra in payments and interest over the life of the loan.

The only people this benefit, truly, are lenders.