but if the Frenchman is as good (or close enough) to the Brit but is cheaper then you are going to hire the Frenchman.
Furthermore if you know there is a steady stream of French that are all prepared to accept lower rates then your subsequent job postings are going to be based on that.
Lets face it though, most of the debate isn't about the levels of western Europeans in companies. People from similar economies are always going to have similar expectations and therefore more even competition.
The only way that companies aren't finding skilled labour locally is because they don't want to pay for it. They are used to a cheap, good enough workers and don't want to accept that skilled workers are expensive because they are skilled.