See this is exactly what I mean when people discuss this chart, it's a shame really.
Did I come across the chart when I ventured into building my first AR? Sure. But after looking at all the info and then looking at the subsequent cost I couldn't justify a $1400-$1600 Colt versus a similar set up from Stag at under $1k.
A lot of folks that want to get into the AR platform don't want to or can't afford to lay out $1500 and then some. And if you think about the recreational shooter/hunter why would they, especially when they can get into an AK platform for $500-$600? Look at some of the folks that choose a caliber based on costs? A rifle is the same thing, what can one afford versus what they want to do?
Sure the chart has useful info but that doesn't not make it the end all be all of AR building. Unless you are in combat on a daily basis I see no need to use/abuse one's AR to the point of Military standards.
The rifle doesn't make the shooter, practice does