I often hear that from founders and CEOs, who said that their job is to be effective, rather than to make people happy.
However, it is important to not forget what happy is a very board term. If you do it over a spectrum it would include jolly, narrow sense of happy, and satisfied.
Founders are not there to make their employees jolly, and may or may not care about the narrow sense of ‘happy’.
But certainly they need to make everyone with them satisfied – only then they can be motivated for the long term.