Apple fans were always going to go wild for the iPad. It's an aspirational product and they know how to use it already. But Apple fans buy expensive hardware and want the newest, shiniest thing. It's not the 'cult of Jobs' aspect that drives huge sales - it's Apple's power with the people who have the money in their wallets to buy the kit.
For everyone else, I don't think it's just that other tablets are in Apple's huge shadow that causes the problem. I think that at the root of this, there's also something to be said for the fact that replacing computers is, for the home user, becoming more optional.
I've been replacing my laptops every three years - an Evesham (I know), then a Dell (again), and most recently one of those shiny new MacBook Pro 13" jobs. The first one I replaced because it was single-core and low on RAM, and it wasn't keeping up with everything I wanted to do with it. But the Dell was still perfectly fast and looked the part after three years of moderate use and despite running Vista. I replaced it only because the case was starting to fail - and now it will be reused as a backup and media streaming device - after all, it runs quietly.
I haven't bought an iPad. And I won't be buying any sort of tablet. This isn't because I don't want one. I can afford one too. But there's no compelling use case for which one of my existing devices won't do a very good job. And that would be the same if I hadn't bought a MacBook.
Recession or no recession, people don't want to spend the thick end of £500 on something that doesn't make their life that much easier, unless they only care about the shiny. And if you care about the shiny, then Apple's the brand for it. HP aren't cool like Apple are, despite the loveliness of WebOS.