If you want to find the optimal number look at how many hours startup founders put in. Incentives are 100% aligned in how they benefit from their work. They have no incentive to work less or more than the optimal number of hours.
Nor are their incentives necessarily aligned properly - if you assume a startup founder is trying to start a business that will make them wealthy, then they may be operating under the assumption that more hours now == fewer later. So a founder may happily push themselves to pull 80 hour weeks thinking that a few years of that pace will pay off so they can coast later.
Most startups fail, and I'd imagine most founders ultimately wind up working for other people. So they'll never get back that additional time + they'll have to keep putting in hours on someone else's behalf.
Exactly. The reason the rank and file don't put that kind of time is they aren't given nearly as generous terms.
This isn't really a discussion of what people can do, people can do much more than they are in general, but instead the problem is how much of the fruits of the effort is willing to be shared.
If I am paid $10/hr for my work I can't eat. My incentives are not aligned. You dont pay me enough to eat.
If I am paid $xxx/hr for my work but I am bound by NDA and non-compete, don't get bonuses in line with product sales (N% of sales go to my check), etc I am not aligned.
The only people "aligned" are the most useless. Sales. Yes, things need to be sold but if the people laboring are not incentivized sales will be useless along with the entire C-suite.
There is no such thing as a "sufficiently incentivized" laborer unless you're paying them a chunk of sales (see: a co-op). Hence why anti-work is such a popular concept even among the highest paid cohorts. Even as developers, we are being robbed blind and are worth far more than they pay. There's a simple test for this: if you work 20 more hours next week will your check potentially go up significantly? If not, your labor is being stolen from you.
[1] If startup founders know their optimal number of hours, why wouldn't regular employees also know this? Why do you think that startup founders have privileged knowledge in this regard?
Plenty of startups go bankrupt and plenty of founders experience burnout, back pain, RSI etc.
Very few people can work 40+ full hours hunched on a keyboard for 3-4 decades.