During the years of development, WoW improved in several ways. The "hard work" moneymaking was shifted from mindless grinding to daily quests. The kill 10 wolves was changed to phased "ride on storm giant" quests. The "you need the prot warriors of half of the world to beat the 4 horsemen" was changed to "you have one hour/week to kill Algalon".
Yet it's the latest tradeskill, inscription that is obviously the most messed up. Let me explain why: tradeskills are mostly for making money. They give some special bonuses, but they are all equalized (or supposed to be), so raiding does not really force you to have one and only one tradeskill. So let's see how can you make money with various tradeskills.
At first let's clarify that while all tradeskills are able to craft items of lower levels, - beside twinks - no one buy them. Even a braindead can level to 80 in greens. Only top level players pay gold to buy crafted items.
Blacksmiths, tailors, leatherworkers, engineers craft epic items. They are expensive, but pretty good. Some of them are BiS, others are "good starter items" and more or less must have to get into any decent guild. There are not many types of these items, for example blacksmithing crafts 21 epics. You check the AH price, check the material price, check competition and craft one. If it sells, you craft another. Simple.
Alchemy, enchanting and JC are more focused on "accessories". While the previous tradeskills also had some enchanments like belt buckles, these three are focused on these. However the number of gems, enchants and flasks are limited. For alchemy, you sell 6 flasks and 5 potions. For gems there are SP, AP, Stam, +hit gems and 5 types of meta. For enchants, there are 6 slots for tanks, healers, spell DPS, melee DPS, max 24 enchant, actually rather 14-16.
Inscription has 341 type of glyphs. Each and every glyph can be used by max level characters. OK, most of them are not used by skilled players, but unlike in gear, there is no tool for the morons to identify which is better. Ilvl 226 is better than ilvl 200, purple is better than blue, and hopefully even a moron can find out that a +agi epic is not the best for a mage. For glyphs there is no help, so they buy lot of types.
This means that anyone who wants to make money from glyphs must sell lot of different kind of glyphs. There is market for 150 runed scarlet ruby/week. Maybe not for you, but someone can sell that amount. No one can sell 150 glyph of nourish or glyph of rejuvenation. Why? At first becaue only restodruids buy it, while scarlet ruby is good for all healers and spell DPS. Secondly, because there are still morons who buy glyph of innervate and such. A businessmen can't teach his customers. I can't tell the idiot to get a decent glyph. If I want his money, I must supply what he demands.
So here I am, having two alts with 4 32 slot inscription bags full of glyphs. That's about 250 different kind of glyphs. I post 4-8 of each type (totaling 1500+ individual glyphs) every 2 days.
I use two alts, 5 addons, mass cancel macro, 800G worth of materials every two days. That get me my 10000+/week income. It's not much of human work, less than 1 hour of time every two days. But it needs such an infrastructure, such a research and focus that is unlikely in everyone who focuses on other game aspects and want to get some gold in 10 mins.
If you are a BS, you can make gold in 10 mins. You check the titansteel weapons in the AH and if you see one above material prices +200G or missing, you craft it and list it. The money will be in your mailbox, or the item returned to be listed again a bit lower.
On the other hand if you want to make money from glyphs, you have to do it as I do, or don't do it at all. If you just craft some random glyph, you most probably sell nothing. Glyph prices shift very fast, driven by random sellers, random buyers and the ever changing "flavor of the month".
On the top of that, even the materials for glyphs are inscribe-made and random, so the "LF for BS for [titansteel destroyer] have mats" is inconvenient for glyph-buyers, they must buy from the AH.
I start to realize that when I say "go sell glyphs", it's like Kungen saying "farm Mimiron hard mode". Trivial for someone who has the skills and the infrastructure, impossible for others.
I was rich before the inscription. I had like 50K, collected by a years' careful AH and furgal spending. After inscription I started to make 10K/week, reaching gold cap in 4 months.
On the one hand I could say I'm using a loophole in the system, an unneccessary complication that is too much for 99% of the players (some doesn't care that much, others couldn't understand). On the other hand in the real world every really big business is like this. Finding something that is there, but unconquerable (or even undetectable) for the others and take it.
Blizzard managed to create something that is so HC, both for creation and buyer selection that it would fit into the old Naxx40 ages and not WotLK. Imagine a gem saying "increase the effect of next Regrowth spell if a Regrowth is active on target"! Of course I'm not complaining, I'm just saying that making all other profession easy-mode and one to uber-HC makes a certain unbalance: you either do this, or you'll have hard time making lot of money. Of course you can make enough, but if you want "a lot", inscription is must be.
I don't know how could the genie be pushed back to the bottle. I guess it would be quite an uproar if the whole profession is deleted. Maybe a simplifying where every glyph does "+10% damage/healing to its corresponding spell" is in order. I don't know.
One thing is sure: this thing is messed up. "Messed up" means "profit" in goblin language.