2 parts already mentioned, they will be changing the way you can learn the missing items instead of books. I think it is Northrend research. That was mentioned in a dev Q & A (mentioned above). You don't really want to farm them yourself. I know it is a shame that you can in theory, but it won't be worth it. Think of it as time invested.
10000 people on server, low drop rates (.1 or .2%). That is enough to give a few to the population. But if 9800 people are in Cata content, and only 80 people instance instead of quest, then you have a VERY low chance of seeing them, hence the 200-300G price. Even if you farm your heart out, you are no were near the number of people that they based the drop on (9800 people in WotLK). You won't be able to get enough kills in to make it worth it. Just deal with how you can.
Ask others to make the item (glyph) for you. I have never had a problem getting ink and asking for 5 glyphs. Buy one book a week so the over pricing doesn't seem so bad. Bide your time until they change how you get glyphs. From the time they mention stuff until it happens seems 1-2 patches, so by 4.4, you should see a change. Good luck.