I'm not sure what conversation you're participating in, but the parent comment was flippantly discussing the possibility of taxes so draconain that the GIDI coefficient would approach zero:

"The wealthy kind of are an endless source of loot because the definition of wealthy is one relative to a median, so you'll either end up with everyone roughly equal in wealth (is that a bad thing?) "

In the world advocated for in that comment, with aggressively averaged out income/wealth, there is no incentive to produce value above what is required to reach the average income.