People who are working 40 hours a week have no capacity to take on some important task with no notice unless they go past 40 hours a week. Which generally doesn't cost any extra money.
Which is the problem. What we need is overtime for all. Time and a half after 8 hours in a day. Time and a half after 40 hours in a week. Time and a half after 5 days in a week. Double time on Sunday. Minimum of 4 hours of pay per workday or if called in. Those factors multiply. That's not at all unusual in union shops.
I don't disagree with you at all. If you regularly exceed 40 hours with exempt employees (especially developers) the compensation structure will have to reflect that or you will have retention problems.
That cost is far more transparent when dealing with hourly contractors, and maybe the employer prefers this! But, you know, theory of the firm etc tells us that in the long run you are usually better off with exempt employees even if they are frequently working less than the 40 hours you expect from them.
Which is the problem. What we need is overtime for all. Time and a half after 8 hours in a day. Time and a half after 40 hours in a week. Time and a half after 5 days in a week. Double time on Sunday. Minimum of 4 hours of pay per workday or if called in. Those factors multiply. That's not at all unusual in union shops.