Ever tried making a magazine? It's a little more involved than whipping out a decent cup of coffee. Having worked in manufacturing for years and based on projects I've worked on, I think mags are one of the more fairly priced gun accessories out there. Well, during periods of non-hysteria, at least. $150 for a Glock magazine is pretty much absurd no matter how you look at it.
You took the words right out of my mouth. I noticed last night that he was posting one sentence threads in every forum. Looked at his post count and seen he was trying to race to 50 so he could make it in the classifieds.
They can wear out or get damaged if you are playing run and gun games dropping mags on the ground, stepping on them etc.
It may also be like buying replacement auto parts. If you buy OE, you will pay. You can get lower prices in the aftermarket, but contrary to what some people believe the OE stuff is usually better than the aftermarket.
I do think they are pricey though and hard to obtain. It would seem like supply would be good. It not like ammo. Not everyone with a gun is ordering large quantities of mags. If you are not gaming, you could do fine with a couple mags.