"and FWIW you can buy yourself honored with sons of hodir for that shoulder enchant for way way way way less than it would cost to power level inscription. "

As an example, compare the Exalted shoulder enchant from Sons of Hodir:
Greater Inscription of the Axe
Binds when picked up
Requires Level 80
Requires The Sons of Hodir - Exalted
Use: Permanently adds 40 attack power and 15 critical strike rating to shoulder armor. Does not stack with other enchantments for the selected equipment slot. Requires a level 60 or higher item.

Now here is the self-only Inscriptionist shoulder enchant:
Master's Inscription of the Axe
4 sec cast
Requires Miscellaneous, Cloth, Leather, Mail, Plate
Reagents:
Snowfall Ink
Permanently adds 104 attack power and 15 critical strike rating to shoulder armor.
Can only be applied to your own armor, and doing so will cause it to become soulbound.

Please don't say that you can get the Sons of Hordir enchant easier. It's also worth less. 140 AP > 40 AP. They're all that way. That's the perk for being an inscriptionist.

"There is some money to be made with enchanting scrolls, but to be honest its often cheaper and easier to buy a stack of vellums off the AH than it is to make them yourself. "

Blank Vellums were going for insane amounts on my server until recently. They've finally dropped down to 15-20g apiece (They used to go for 50+). It's still far cheaper to make them myself. Again, if you have herbalism and get the mats yourself while out questing, these are practically free to make.

"After that, I stopped because farming took too long, and buying the mats was absurd for the price that was asked. "

Any profession where you resort to buying mats off the AH to level is going to be expensive. Imagine the cost of Engineering if you bought all of your mats... If you farm them yourself there is very little cost involved in leveling up inscription. Since I was leveling herbalism anyhow, I just mailed all of the herbs to my inscriptionist.

No one is going to say Inscription is the best profession in the game. It's not essential to have an inscriptionist in your team or on your main character. But it's not bad to have on an alt (especially an alt you don't plan on grinding out Hodir rep with any time soon). If you're leveling enchanting on any of your characters, there is no reason to waste enchants - inscription can save hundreds of gold worth of mats while struggling to reach max enchanting. The return on your investment might not seem like much (glyphs don't sell well at all, you just use them to level up skill - a point I've complained about in the past), but it's such a cheap profession that it's practically impossible to lose money on it. The longer I've had the profession, the more I've come to appreciate some of its benefits.