My assumption is that any company that's going to go down this track is trying to make it work, trying to make it useful, and trying to improve the employee's life and hence their happiness and productivity.
Your assumption is that the company is going to take the work that would have been done in that time off and force the employee to do that work anyway, but in the smaller amount of time they have available.
People with that point of view are valuable in some contexts because they can see how things won't work, can never be made to work, and in response will demand things that they know will work. For them.
The upshot is that, like most people, not every work environment will suit you. If I ran a company like this, and if a policy like this makes you head for the door, I would offer you free use of the company's facilities to help you find a place you would be better suited and unlimited time off to search for and interview at places you feel would suit you better.