In the USA maybe, but there's more to the world than America
Yes! The colonies are top market in Blu Ray sales, and most likely represents more in total sales than the rest of the top 10 world marketplaces combined (inlcudind UK). However, Blu Ray sales in the UK have increased by over 50% in the last few years and represent the same proportion of sales vs DVD that are here in the US - DVD is still the dominant format but sales are decreasing every year by the same amount that Blu Ray increases - worldwide.
The world is bigger than the view outside your window (or a trip down to the local mart).