This causes minimal hard to a business and zero harm to Musk's ability to afford yachts. But a very large number of employees have jobs because they need to pay

This causes minimal hard to a business and zero harm to Musk's ability to afford yachts. But a very large number of employees have jobs because they need to pay rent and buy food. Losing that job is a significant change to their lives. Software engineers are more likely to have large savings that make it easier for them to say "fuck you" to their boss and leave but in general this system of at will employment is not actually balanced.