One outflow, split two ways
For the same face amount the whole-life premium is larger because it contains a savings piece: the level premium covers the death benefit and, on top of that, funds the cash value. The page takes the difference between the two monthly premiums as the amount both sides commit - the defaults are $235 against $35 on $500,000 of cover, so $200 a month - and that is what keeps the comparison fair. The term household is not spending less; it is putting the same money somewhere else.
If the whole-life premium comes in below the term premium, the gap is floored at zero rather than going negative, and a warning note says so in plain words. With no extra budget entered, every row of the table is then zero. That is a statement about the two quotes rather than a verdict on either policy, and it usually means the face amounts or the medical ratings differ between them.