Although I could have expressed myself better, you still quoted me out of context. I was particularly talking about people dealing with less sleep on a relatively small timescale (less than 3 months). I'm choosing the 3 month window because it replicates the length of a college term and greatly reduces the risk of burnout (which I don't think is as big of an issue in college as in industry, because typical college schedules give at least a few weeks off after each term).
Are there any studies that compare how much people can done in a few months on different sleep schedules? I'm imagining some sort of cognitive task (like reading books and passing a comprehension test, or working through all the proofs in a math book) where the goal of the participants in the experiment is to accomplish said task as many times as possible in a fixed time period. This would be very difficult to design because one needs to decide on cognitive difficulty for the task (if the task was very easy, then less sleep = more time would almost certainly help) and have roughly equivalent ability between the 2 groups. This study wouldn't capture dealing with context switches or retention of information; just how much can be done in a fixed time period.
As far as I know, such a study doesn't exist. Anecdotally, I've seen many people make the decision to trade sleep for more time even while working on cognitively difficult tasks. Personally, I feel like I accomplished more during my terms in school than I could have sleeping 7+ hours/night.
On the other hand, I acknowledge long term sleep deprivation is not good for long term health, and I've personally seen my ability to run with intensity suffer during periods of low sleep.
In summary, I don't doubt the long term effects of low sleep on health, I slightly doubt the negative long term effects of sleep on productivity (know people who have been doing uberman for years and swear by it), and I heavily doubt that people can't be more productive over <3 month window by sleeping less than the recommended 8 hours per day.