If I bought the materials for £80, all I'd be able to make at home would be a hell of a mess. I don't think the prices are too bad, so long as the quality is good, although ready made furniture will always look expensive next to flat pack stuff. Not necessarily a problem as long as it well enough put together to justify the difference.
I can see a market for the games tables amonst people who have enough space to have their own games room and want an all in one gaming/storage space solution - the obvious problem I see with the flip top desk is that most hobby desks I've seen have far too many bits and pieces and works in progress on them for them to ever be used like that. The shelves... well, I don't really see the need to buy a bespoke solution for shelves - I mean, they're shelves; most of the ones you can buy are adjustable enough that you can get them to be the right size for whatever cases you use anyway.