Hmm. I guess it's because the Egg Beaters lasts longer and doesn't make me feel wasteful by throwing out perfectly good egg yolks.
However, since eggs are generally cheaper in the UK, you might be right (I was still thinking US prices, probably).
Seems like they'd be around for the health-conscious, but there's also definitely a smaller proportion of "diet"-type foods here, I think. Not complaining, just an observation of culture.