I'm not sure the pool of talent is actually that big. Live, unscripted TV isn't something everyone can cope with. One of the reasons why QVC went for news presenters for their most recent recruits (Marv, Jackie, Chloe (sports news)) is that they are used to broadcasting live, with a talkback pack. The more gifted can do it and be themselves (like them or loathe them)... others make it look like hard work, unfortunately, however experienced they may be.
It's the same reason why presenters seem to pop up over and over again when they leave one shopping channel they are soon seen at another (hence the permanent return of the rude Sara Griffiths after covering for Pipa's sabbatical).
QVC seem to have become increasingly risk averse (as illustrated by the increasingly unimaginative and repetitive TSVs), and getting someone in who has no selly-telly or live unscripted broadcasting experience would be too big a risk for them. QVC isn't a training ground or launch pad for someone's glittering television career, it's either a final resting point or it's a marking time job until something better turns up. It seems to pay well enough, and if you're self-employed as it would appear to be the case for the presenters, having a steady income which makes sure you're financially stable is an attractive proposition.
If the presenters are self-employed, they will be on contracts with a renewal clause in them. It will be the presenters' choice to renew or not if that offer is made to them... equally, it will be QVC's choice whether or not to make a renewal offer. In deciding whether or not to offer a contract renewal, QVC will be more concerned about sales performance during a presenter's hours rather than viewing figures. Let's face it, it doesn't matter how many of us watch or don't watch... what actually matters is whether people buy on a shopping channel.
