Is indeed an issue, as it corresponds with the malaise you describe.
> wage stagnation
is in part due to the government increasing the costs of hiring people. That indirectly results in correspondingly lower wages. The so-called "employers' contribution" is a misrepresentation.
This is lazy thinking. If the government is indeed increasing costs, this is happening to everyone across the board. So why would anyone in particular be affected by this? It could even be true in a situation where profits were falling across the economy, but the numbers show that profits are INCREASING for most companies in the US at least. So how can these companies justify that it is the government forcing them to hire less people if they have more money every year?
If? It's a certainty. For starters, the only reason HR departments exist is to try to comply with all the regulations. HR departments are expensive. For seconds, all the "employer contributions" to payroll taxes. Then there are all the wage laws, and mandatory this, and mandated that.
All increase costs of employing people, which comes out of the employees' pockets one way or another.
Profits do not drive employment. What drives employment is the employee provides more value than they cost to hire.
Yes, it does, because what the employer cares about is the cost of having the employee vs the value that the employee delivers. Cost of raw materials is not relevant.
> they whine
I recommend you start a business and test your theories!
Subjectively I doubt that that is a systematic driver of income inequality. For example in 60s the taxes in the higher margins were extremely high (80% I think?) and worker bargaining power was strong. Yet it was a period of unprecedented growth and innovation, one where ideas of invisible hand and tide that lifts all boats were forged but in reality it was not a laissez-fair period at all.