If Bezos really wanted to put his money where his mouth is, he would implement a minimum mandatory vacation period and significant maternity/paternity leave at the least, if not a max # of hours per week.
Of course, that would not maximize profits at amazon or most other companies so that's not really what will happen.
I don't think the assumption that long hours and little vacation maximize profits should be taken for granted, especially in a longer-term time frame. I've seen quite a lot of information in the past few years that shows that (especially for developers) long hours have diminishing returns on productivity, and may actually hurt productivity.
It may hurt productivity, but the employer gets the benefit of keeping the employee on a leash by not giving them time to look for other opportunities , plus in some businesses you can just keep grinding employees to the bone and sift until you have the most workaholic ones, such as in finance.
I won't claim to know what will happen to Amazon or other companies if they keep trying to squeeze every cent out of every employee all the time, but in my professional circles of people who work front office at investment firms or consulting firms (in the northeast), there is a long history of making sure the newbies are in the office 80+ hours a week. These are also the same firms that continue to make the most money year after year, so I would assume there is some possibility to extract extra value from the subset of the population that is workaholic.
I think this is something that varies a lot based on the nature of the work. Creative software development/design/engineering is more taxing in a way that precludes almost anyone from being productive at an 80+ hour/week level, especially if it is the "normal" workload.
Not to diminish finance people, by the way. I'm sure they work hard, but in a different way.
A client had an interesting system along this line. Every employee was required to leave for one week to make sure that day to day operations continued without interruption in their absence. As result, everyone took at least one week of vacation. Often they would take two at this time.
Funny thing is, Amazon has never really been into maximizing profits, at least in comparison to re-investing the company in new experimental directions. An investment in their own employee's well being seems to be something in line with that. But, I'm not a CEO.
Technically, Amazon might not be into maximizing profit via cash flow. But Bezos certainly has an interest in maximizing share price, via undercutting competitors and offering the cheapest prices and maximizing market share, thereby leading to a possibility of increasing profits via sales. Any which way, squeezing every cent out of the employees will work towards accomplishing these goals. So while they may not have a ton of profit in the traditional sense, it's still all the same interests reaping the gains they always have.
Of course, that would not maximize profits at amazon or most other companies so that's not really what will happen.