It’s an equal trade, in theory. The worker gets a fair wage AND no risk, and the employer gets work out of them, probably somewhat above and beyond what they’re paying them. Ideally the assumption of no risk (i.e. the employee keeps getting paid if the company isn’t making profits, etc…) is roughly equal to the amount of value the employer gets from the worker above and beyond what they pay the worker.
Under state equivalents, perhaps, but under the federal FMLA there is no difference between 100 and 1000. Maybe you’re thinking of the 1,250 hours required for an employee to be covered.
If the employee can’t do work that yields more than his salary, he can and will get fired. However the employer needs to set up the job so success is possible.
If the employee produces many times his salary, and there is an excess of available labor out there, he may not get more than the MW anyway. There is nothing requiring an employer to pay what an employee is worth in terms of productivity if there is a glut of labor on the market.
Yes, right now, individual laws tend to have on/off characteristics at a particular number. It does look like something like a continuum when you take all of the different laws into account, though. For example, Seattle has a law requiring paid time off if you have 5 or more employees. COBRA coverage must be offered at 20 or more. Right now, ACA mandates are only at 100 employees. SSA doesn’t require electronic filing of W-2s until 250 employees.
So that random sampling of laws imposes new employer compliance issues at 5, 20, 50, 100 and 250 employees. That makes it very close to a continuum from the employer’s perspective.
Only if the employer can’t distinguish between the different laws. The OP is presumably not talking about passing his new minimum wage mandates in multiple pieces of legislation.