Really? I didn't know that!
I knew that cadets were sourced through one company, however that isn't a "monopoly" position, as there are a number of schools that compete in this marketplace. One may be contracted at any given time, but just as with fuel suppliers, handling agents, caterers, etc. value is always under review.
Outside of the cadet requirement, "experienced" F/O's are recruited from the traditional sources and generally in accordance with the minimum levels of experience required, which are significantly in excess of what might be termed "low experience."
At the present time, recent commercial events have resulted in a number of qualified, current, type rated and experienced pilots being available in the marketplace. I am sure that a proportion of pilots from these sources are being considered for the current round of projected vacancies.