AR’s are cheep now. He doesn’t say how much he paid for all the parts but I would imagine it was a lot more than a stock Bushmaster, Delton, Core, S&W or whatever.
And that’s not including his time and the cost of correcting mistakes.
Why not let people who use CNC machinery and know what they’re doing do it? So he can say he built an AR in his kitchen?
For one primary reason - it is a ghost gun, meaning that neither the Feds nor the state know of the existence of that gun (lower receiver).
I did a cost analysis on this and AS A GENERAL RULE, the 1st AR is going to be slightly more (say 20%) by the time you buy the tools, gigs, blanks etc. However, if you already have a drill press and a Dremel, the costs are slightly less. You still have to buy the upper and the trigger assembly and the stock so the cost savings are not significant.
If however, you are going to make more than one AR, (perhaps allow your buddies to use your equipment) then the cost drops below what you can buy it for from the market. Again, not significantly.
Last week Gander Mountain was selling Ruger's AR clone for $699