Historically speaking, income streams are worth 20 to 25 times their annual payment. Like, there's examples of this ratio from France in the 1400s, IIRC. So $5k/mo = $60k/y = $1200k. Granted, this doesn't take into account how annuities generally don't pay to a recipient's heirs, so there's an actuarial table discount to take the ratio down.