In equilibrium, people get paid according to their productivity. (That's why eg China saw such huge wage raises over the last decades.)
So, just excluding or including some more people won't change the level of pay, as a first order effect.
There's no constant demand for labour. It expands and shrinks with supply. (And even then, the federal reserve can make arbitrary large amouts of demand. They can literally print money.)
>In equilibrium, people get paid according to their productivity
But where and when has there ever been this magical equilibrium?
In the real world people get paid whatever they can get away with, and some people can get away with more than others. Telecommunications execs can price gouge you and get a bonus for it.
>For the economy as a whole, abstracting away imports and exports, we can only eat what we sow.
Exactly. And "we" after all is another abstraction. And "I" can eat what "you" sowed.
If corporations have record-high profits, while workers get stagnating salaries while housing prices raise, someone is going to realize what "we" entices after all.
So, just excluding or including some more people won't change the level of pay, as a first order effect.
There's no constant demand for labour. It expands and shrinks with supply. (And even then, the federal reserve can make arbitrary large amouts of demand. They can literally print money.)