But this is really a fact. The economy of World of Warcraft is a lot simpler, but the same basic truths apply: The market value of items, in this case glyphs, has nothing to do with any fundamental value of that glyph, and everything to do with supply and demand. Inscription is a new profession, so many people learn it just because it is new. And to skill up, they can only make major glyphs, as those are the recipes learned from the trainers. The minor glyphs are learned by research, one recipe per day. Because people are impatient, want to skill up fast, and have excess money to burn, they buy the ingredients (herbs).
Then they produce lots of major glyphs, which floods the market, and drives the prices down. In the end they paid more for the ingredients than they get back for selling the glyphs, accepting that skilling up a profession means losing money. But as nobody makes minor glyphs to skill up, and everyone has only a few minor glyph recipes compared to lots of major glyph recipes, the minor glyphs are relatively rare. And although their effect is often just cosmetic (polymorph penguin for example), some people are still willing to pay for that. So it comes that minor glyphs sell wow account for considerably more than major glyphs. I check the AH every day for all minor glyphs that I can make, and then only produce those where the current market price is over 20 world of warcraft gold, which is my standard sales price. As even with high herb prices I can make that glyph for about 10 wow gold, I'm making money. Plus often I don't pay that 10 gold, but gather the herbs myself, so I only incur an opportunity cost.
With major glyphs starting to creep up in value, things like the Glyph of Consecrate and Glyph of Icy Veins are both holding at 30g - way above their production cost - and both are major glyphs. I'm wow power leveling the skill later than most, and stretching it out because I don't want to pat ridiculous herb fees.... the upshot is that its been paying off with increased prices on the majors I have to make to skill-up.
I don't see glyphs holding much value long-term. For the most part, once you've got a couple of glyphs, you'll only change them if you change spec, or discover a dramatic improvement in strategy you could use new glyphs come on the market.