Because we're being ripped off
I was in Denver last week and visited Best Buy at Park Meadows (on County Line Road if you've ever been there) where they have an ASUS Transformer on sale for $399 - that's about £250. The exact same device on Amazon starts at £349 and some are trying to flog them for well over £400. At EBuyer its £359 ex VAT! That's £100-£160, $160-$250, 40%-60+% more.
In the internet age, that's shameless. The same seems to be happening with all kit. Is it surprising that in a largely technophobic nation folks are finding the modest investment in a smartphone and the occasional visit to Maplins for spares is a good substitute for way more cash than their friends over the channel or their cousins over the pond have to fork out?