I think that although the Celtic and Co jumper is more expensive than many others linked to, you need to remember that wool is more expensive than acrylic and that Celtic have their clothes made either in UK or in Europe so they are mostly likely paying more to the workers who are making their clothes .
However regarding washing it, remember that a high neck sweater is going to have the neck next to your skin, rather than if you bought a round neck or v neck style you could put a shirt underneath it so you could get away with washing it less .