I fail to understand your post: it's neither a novel idea to compensate extra for overtime nor did I claim it was. I just said that I found this to work well.
I see unpaid overtime as one of the primary drivers of extreme crunch abuse. It aligns incentives in the worst possible way: More work gets done per week (though only marginally at best), project management gets to claim "we're doing all we can" and then, on top it's actually free time donated by the employees at no immediately obvious costs. Not surprising that this sounds attractive.
I've struggled for years trying to get my headspace into the right place to deal with salaried work. I've got a very blue-collar background, and my first few jobs were in those kind of hard-hat & steel-toe boot industries, where you literally punch in and out, and your compensation is directly tied to the number of hours worked. In those situations, the calculus you're describing about "does this need to be done now, or can it be done tomorrow?" already takes place, since unpaid overtime is illegal, and if you need more than 40 hours in a week from an employee, you have to pay the premium for it.
It's less of a salaried work issue, it's more one of people not knowing or not caring about their rights. I can't talk about the US landscape but in germany unlimited unpaid overtime is not legal, still you see that often in work contracts, especially in contracts in startups and web/multimedia agencies. Its especially common where unions and other organizations that could enforce legal limits are weak. I've for example never seen such a clause (and unpaid overtime) in organizations where a strong worker rights position existed.
I see unpaid overtime as one of the primary drivers of extreme crunch abuse. It aligns incentives in the worst possible way: More work gets done per week (though only marginally at best), project management gets to claim "we're doing all we can" and then, on top it's actually free time donated by the employees at no immediately obvious costs. Not surprising that this sounds attractive.