Why are companies in general opposed to employees working shorter hours?
Shorter hours means less expenses for salaries. And while a lot of the fixed costs for office space and stay the same, this argument is less valid for companies where a lot of employees work at the client's place. At the same time it could give them a competitive advantage when hiring, which is important in fields where people are hard to find (software development) and recruiters charge a lot.
The issue has become even more important now with coronavirus and the schools having shut down. My employer wants me to use holiday-time to make up for missed hours. I would much rather take a temporary pay-cut and spend the holidays holidaying. Knowing an answer to this question could help me negotiate.
The context is Europe, specifically the Netherlands. This may be relevant, because I believe that on top of salary, employers have other costs per employee that may influence the calculation.