Its a combination of loads of factors, Anime News Network had a terrific series of articles which explained it much better than I could:
Part 1 - Let's Make an Anime
Part 2 - Shiny Discs. This is the one that explains it!
Part 3 - Digital Pennies
The following is my personal take on the matter, it in no way represents a 100% accurate view, but rather the situation as I understand it. Someone correct me if I'm making the wrong assumptions!
Essentially, anime is a super niche product that relies on a very loyal, very small subset of fans to pay for its production costs. It's a very unique model...but I think it's very dangerous and short-term. On the plus side, you get a load of quirky titles that in no way would exist normally as they go against the mainstream. The physical editions are also packed with nice bonus stuff like soundtracks and artbooks to make it appealing. On the minus side, you're utterly reliant on getting this small number of fans to cough up the super-high prices, so you have to really appeal to them. And if they demand "Moe Moe Panty Flash Childhood Friend's Hips Are Moving On Their Own Baka Oniichan!!! <3", then that's what you're going to get loads of!
Of course this completely flies against the model we have here in Europe and in the US, that of boxsets containing whole seasons sold at very nice prices to a much higher volume of people. That's the challenge that Western anime companies have to face. The Japanese model will not work here, and the number of anime fans is nowhere near large enough to support huge volume sales the way something like Game of Thrones would. The Western model also brings about another threat: Reverse Importation. With the growth of the internet and globalisation, savvy Japanese fans realise they can get things a lot cheaper overseas and import...but anime is so reliant on domestic sales that the whole business model collapses and there'd be no more anime!
So that's why foreign releases tend to be inferior, it's crucial that the high priced Japanese releases sell to keep the companies afloat! There've been many strategies to do this, whether it's by delaying international releases sufficiently from the Japanese release, being uncooperative about providing materials or region locking whenever possible (Persona 4 Arena is the most shameless example of this...and Europe predictably lose out as a result).
With the advent of Blu-ray another problem arose, some bright spark put the US and Japan in the same region code! This took away region-locking as an option to protect domestic sales, so that's why we get shenanigans such as locked subtitles, no Japanese audio tracks, no features, or in the case of Kadokawa, no blu-rays at all! (Though Panty & Stocking suggests that this is changing to long delayed blu-ray). It's all about making them as undesirable to Japanese fans as possible! Of course if you go too far, you'll piss off the international fans...but we're just bonus money on top of the main concern which is the domestic market. And why blame them? They've somehow managed to make an environment where a 2 episode blu-ray can sell thousands of copies at about £70-80 a pop! Compared to £20-30 for whole series boxsets around here or even
ALL of Lost for £59, any business minded company would stick to whichever is the most profitable! We basically have to make do with what we get.
As part of Region B, we in theory should benefit as reverse importation will be less of a problem (hello region-free Blu-ray player!), and indeed, in mainland Europe, Kaze have been doing some very nice things. The market is big enough there that they can produce their own French and German dubs, or just release sub-only. The UK is a lot smaller however, and also we're reliant on English dub materials coming from America most of the time (with the occasional exception, like Professor Layton, Musashi and Welcome to the Space Show), and on masters and stuff to come from Australia (who we share both PAL video for DVDs and Region B for blurays, and they have a stronger market so Manga often use their discs as a starting point). I think Kaze at least are starting to change things by integrating us with Europe more so that should benefit us greatly.
So yeah, I think I might have gone on a bit there...but yeah I hope I helped