^ The answer to life the universe and everything.

That view makes me want to check out today, to be honest!

It is quite interesting how you've linked some things that might not intuitively (as I see it) go together, but I do see what you mean.
The reasons for that long-term drop were cheaper production facilities, more efficient logistics chains, and economies of scale in delivery. The T-shirt you bought in 2000 may well have lasted 10 years but it also almost certainly cost you more than the one in 2010, especially if you were to apply indexation to the 2000 cost.
True.
The changes now are that the production is no longer as cheap, due to an increasing middle class in producing countries causing wage pressures;...
I have no problems whatsoever with fair trading, I think it's a wonderful thing, and about time, too! I do buy a lot of fair trade products, even though they cost a little more.
You want better, you must be prepared to pay more.
I do not mind paying more when the occasion calls for it. What I do mind is underhand, unannounced changes.
When you are very familiar with a place and have been shopping there for years, you tend to start using a type of shorthand - you know what you're looking for, and how it will feel and fit - so you might purchase something without examining it too closely with a magnifying glass as you might be wont to do in unfamiliar surroundings.
After I've taken the item home and worn it, I might absent-mindedly notice something is off with how it feels and settles, I might wonder if I have gained or lost some weight, or if my posture's changed to make it look so different... I might dismiss all that as too baffling and carry on as before, launder it, and put it in a drawer. It might be only then everything clicks into place, and I notice the quality of the materials and workmanship no longer have anything to do with a similar item in the same drawer which I'd bought at the same store at an earlier date. The changes are subtle but significant. The stitching may remain the same, but the thread may be poorer. The cloth may look and feel similar, but fibres may be shorter and more prone to splitting. There may be the same reinforcements around the neck, but the technique of attachment may have changed... these are things you will only probably notice with time.
This pisses me off because it means I have to find elsewhere to shop to maintain a reasonable standard. I enjoy the convenience and simplicity of knowing who stocks what I need. My height and shape are not the easiest to dress, and so I am not able to walk into random shops and try something on with a reasonable expectation that it will look how I want, I am not that lucky, or my tastes are just that funny. Anyway, when I find something that fits well, I stick with it, as it has usually taken a lot of effort to find it in the first place.
Price increases are not pleasant, but it is the fact that I will have to go out and trawl god knows how many more shops for what I want, yet again, that irritates me the most of the two. I would rather they keep their standards high, and crank up the prices as necessary to save me the time and trouble of being misled and annoyed. Or, at least have some sort of display indicating when drastic changes have occurred, so I do not end up buying pretend clothes. Since this display would have to indicate something like: "Attention, we are now more crap than ever before!", it's understandable they don't want to advertise such things. Fool me once and all that though.
I really despise the trend for disposable anything, somebody needs to cater to the type of shopper who is lazy and loyal, and sticks with something when they like it... I don't mean I wear identical uniformal clothes for years and years, there are variations in fashion of course, but the one thing I want to remain steady is the quality. If I give my custom to a shop, it is usually for quality reasons, and if they no longer provide that, I will have to move along, and have had to do so way too many times in a short period of time.
I mean, why not cater to us with good honest doable profit margins, rather than something inflated into a percentage of 100s, maybe 1000s, is that too much to ask?
There are of course a few places that are still very honest, but they are few and far between, and you really have to hunt for them. I am not wealthy, but I still want reasonable quality without going into debt. There are many like me, but not enough, the disposable crowd who will buy just about any kind of crap are ruining it for the rest of us.
What do you expect though, when people are kept so busy trying to work a 9 to 5, keep a roof over their heads, care for their children, have a few hobbies... all life outside of work having to be squeezed into evenings and weekends, the number of chores left to do become overwhelming, and in big cities, every place is crowded and uncomfortable at those times... this type of average person doesn't have time to stand around looking over things with a fine tooth comb. Big business have us where they want us: rushed, harassed, tired, absent-minded, undiscerning consumers - not people who deserve quality of life, but one giant consuming wallet walking around. This nation and many others with it are going to hell in a hand-basket due to insatiable greed. I guess it is the cycle of things... boom and bust, nothing lasts forever, even the super powers. Maybe when the shit really hits the fan, I will have to relocate to keep my quality of life relatively even without suffering too much deterioration, perhaps riding the wave of some other nation's boom phase. Becoming a global citizen might be the only answer to side-steeping inevitable problems like this (if you live long enough to see the cycles).