[lotsofpulp]

I see that example as supporting the idea of supply and demand determining price.

Employers colluded to reduce number of buyers, hence reducing demand, causing sellers to have fewer alternatives to sell their services to, causing them to sell at a lower price than they otherwise would.

There may be more effects due to lack of information or ability to move or issues of social signaling compared to a simple example of widgets, but in the grand scheme of thing, it still follows the same principle.