Increased spending on employee insurance is due to increasing healthcare costs. Even if companies are spending more on their employees healthcare, employees are still paying more on healthcare than ever before. So, that still means less money available for everything that isn't healthcare, and is functionally equivalent to a pay cut.
An increase in spending is an increase in spending, it is still a part of the total compensation an employee has received. My point was purely that lensing the issue through minimum wage by itself seems like a distraction in terms of understanding employee wealth, I'm not arguing that employees should stop wanting more because they're getting enough.