The military doesn't buy from the lowest bidder. If that was true, we'd be issuing our soldiers Olympic Arms and Deltron kit rifles. Instead, Colt is one of the few companies that have contracts with the US military using the specified Technical Data Package, something commercial manufacturers do not have access to (and something most people are unaware exists). This includes even companies like Noveske. Ever see what we pay for a toilet seat or B2 bomber? Low bidder is about the furthest thing from the truth when it comes to defense spending
And for some actual data, we can refer to this for starters:
https://spreadsheets.google.com/spr...akp2a3Y2NjMxTEE&single=true&gid=2&output=html
Now, if you can address and refute the differences in parts and materials outlined in that spreadsheet of allegedly identical firearms, we can move forward in the discussion. Being an engineer, you're well aware that these differences aren't cosmetic. It took a lot of folks prodding companies for years to get exacting details on these rifles' individual components. Somehow I doubt you can dismiss all that hard work with a magic wand.
After addressing that, we can address the opinions of firearms trainers and armorers formed from the experience of witnessing hundreds of students sling thousands of rounds downrange in a training course day in and day out for years and what rifles tend to puke the most.
Then, we can scour the Internet for threads started over the problems of a company's product and see which companies generate the most complains on improper construction or parts failures, such as improper staking of key components, overgassed porting, incorrect buffer weights for reliable operation, and out of spec parts like receiver extensions.