So many ammo resources, why?

I see so much talk about buying in bulk to save money, using ammoseeker, etc. I’m confused on why people look for deals through these methods as I am finding cheap ammo locally pretty often.

I live in the Denver metro area and I have consistently found the best ammo deals at Cabela’s. I don’t know their politics but they seem to have good prices for ammo at least.

Am I just lucky where I live? Unless I buy 2000 rounds that are factory seconds I am not even getting the same price per round as locally.

Also, the ammo prices I am talking about are for Blazer and Armscor 9mm rounds. I trust Blazer but not sure about Armscor but probably more reliable than remanufactured and factory seconds.

Anyway, am I missing something here?