The employer paid out what the job is worth. Which in this case is $16,147.50.
Just as there is no guarantee that they wouldn't make a dime less than $16,147.50.
No, it is set by the market. If the employer thinks he can get away with it, he will pocket the money. But there are other employers that will be content with breaking even (i.e. giving the employee the full amount) because they value the profit that the employee provides.
Here's another example. Let's say the government puts an indirect tax of $1/pack on cigarettes which drives the retail price up to $3/pack. This high price causes some smokers to quit, while other smokers become accustomed to paying the $3 price. Then one day, the government decides to drop it's $1 tax. By your reasoning, every retailer will choose to keep the prices at $3 and pocket the difference. But that premise is false. There will be a retailer who will choose to drop his price back down to $2, keeping the same profit per pack, but hoping to increase sales. So where will the consumers go? Will they keep paying $3 per pack even though they know a retailer selling cigarettes at $2? Of course not. Likewise, the minimum wage worker won't keep the $15K job because he will find an employer willing to give him the $16k+ he has been willing to pay the entire time.
The invisible hand always wins out. People will do what is in their best interest. And for the employer, that means maintaining the status quo by continuing to pay out $16k+.
Take a deep breath and pull your head out.
The prosepctive employee says "what does it pay"? They are told "X" dollars an hour. That is what the paycheck they see is based on.
They don't give a damn about the employer cost of matching Social Security.
They don't give a rat's ass about worker's comp as long as it is there if they need it.
They didn't consider payments into unemployment funds.
They didn't ask how much insurance cost the employer, just if they had it, and what their share was, if any.
They didn't ask what PPE would cost the employer, nor safety training, nor fleet vehicle insurance.
it just comes with the job.
See where this is going?
Those are EMPLOYER COSTS of hiring someone.
The employee
is often unaware of them, and didn't add them in when considering their wages, which is what ends up on their table, after taxes. To the employee, that bottom line is what counts. Their wage is what shows up on their check times the hours worked.
Any reduction in EMPLOYER COSTS
might be shared with the workforce, but there is ABSOLUTELY NO GUARANTEE that is going to happen.
Considering any increase beyond the wages proffered only incurs additional expense for the employer and leaves less wiggle room to give raises if there are market slumps, cutting employer expenses might not be so robustly passed on as you seem to think.
But in all my years in the workforce (going on 53, now) I hired on for the wage, the day rate, and whatever was added in (per diem, expenses, insurance, etc.), but never considered the Employer's costs in that, because the employer had those factored in when they made the offer.
The only time I would have received that difference was when I worked for myself.