* If you have a net worth of $250k and they calculate you can pay $70k for the first year, estimating full payment as $70k * 4 ($280k) isn't right. Your net worth will be lower next year, and they'll consider that.
* Their goal is to charge you the most you are able to pay, and someone with $250k in savings is able to pay $70k.
I think this is all a bad system, for the same reason that a 100% marginal tax rate is a bad idea, but it's not quite as nuts as you're suggesting.