Umm, seriously?
Even if you ignore the likes of the recent Jurassic Park releases, the Fast & Furious franchise and the Marvel releases, of which most were great releases but not UK exclusives, you still have Zavvi's Disney and Pixar range (most of which are fantastic), Daleks: Invasion Earth, 2150AD, The Crow and The Wicker Man, all of which were great steelbooks.
In fact, outside of a few Zavvi exclusives, most UK steelbooks are available elsewhere in the world just with different J-cards. Most US steelbooks are indeed US exclusives, but most of the time their poor finishes let them down. That and the fact that most of their websites don't ship outside the US or charge an arm and a leg to do so, unlike most EU companies which do at a reasonable price.
For every poor UK steelbook (Star Wars trilogy), you get a poor US one (Batman Begins)
For every great UK steelbook (Watchmen), you get a great US one (ironically, Watchmen)
It's the same story worldwide. Even many (but not all) of the sought-after Korean or Blu-fans releases are just the EU edition with a slip over the top.