Because $370 for 13 episodes of an above-average show isn't inflated enough 
First off, you can't really say it's above-average when you haven't seen it. IIRC you still haven't seen it as Fate/stay night is still on-hold for you.
And this is why this release is not for you. Aniplex USA
does not care about the people complaining about the price, they care only for those who are willing to buy this. They're marketing this towards the very passionate fans, people who import anime (There are more people who import Japanese releases than you think. I've run into many, many, many people on various forums who do so.), want it now (You want it same day, you pay import prices.), and or physically with very appealing extras, packaging, and premium items.
They aren't forcing people to get this however as you still will have legal streams on Crunchyroll. This is a better deal than what Garden of Sinners got. You have to keep paying to keep watching it as it's only rentals.
To you it's not worth getting, but to me it is. I got the Rurouni Kenshin: Trust & Betrayal LE BD import. It was $65 (The retail price was $82, the Japanese paid more than $100.) for 4 30 minute OVA episodes, and I couldn't be happier with it (Especially since I absolutely loved T&B. I find it one of the greatest anime ever created.). The value of these sets is different for everyone.
Also if you want true inflation, take a look at how much Garden of Sinners (Made by Type-Moon, the same guys who worked on Fate/Zero.) is going for. At Japanese prices this would definitely be overpriced.
http://www.amazon.com/gp/product/B0040QE5NI/?tag=gtplanet-20
http://www.amazon.com/gp/product/B0040QE5NI/?tag=gtplanet-20
BTW, speaking of imports, I'm willing to import this (It has the English dub, and English subs.) as the chances of this ever coming to America is next to none. The Big O will remain having DVD's only in North America.
http://www.amazon.co.jp/dp/B005AQKWOS/
Conversions from Google:
37800 Japanese yen = 485.4881 US dollars
27717 Japanese yen = 355.9861 US dollars
If you want to know the episode count, it has all 26 episodes (Episodes 14-26 were co-produced by Cartoon Network due to how well it was received here.).
Well, the original is a good place to start, but to be honest I haven't seen it yet, either, and while it launched an epic franchise, most people think it's just good, not great. 00 was however great, especially for being modern and having increased production values. Zeta was better for story though in my opinion. Gundam wing never really attracted my attention, so I can't say, but it looks like it should be last of the four in your to-watch list. I'd say:
1) Gundam (and I'll join you in watching it)
2) Zeta
3) 00
4) Wing
Thanks, guess I'll go with that order.
I'll be done with getting through many of these on-holds in February/March so I'll finally be watching stuff I haven't seen.
), but if you ever get lost, I'm always around to make things worse. 
. Yes I know many episodes... But you can always watch the movies tho.
