I think it's just that it reflects what the buying public demands.
"Back in the day" there were plenty of AR-15's that were junk. Colt had the lock on the market and the aftermarket was mostly sub-standard junk. It wasn't until Colt grip weakened and some companies started to do a better job of quality that the buying public started to gravitate towards the quality guns. Then it was a matter of either producing a quality AR, or going out of business. The introduction of many of the big names into the AR market had further increased the pressure to maintain quality.
50 years as America's front line rifle tends to mature a design.
With the AR-10, there was no "milspec". The parts aren't interchangeable on many. Heck, they couldn't even settle on using the same mag for the longest time. The market forces are not as strong with the AR-10, simply because the market itself is relatively small compared to the AR-15. It's going to take some time for the AR-10 market to sort itself out.
Last edited by Ross3914; 03-14-2017 at 05:02 AM.