Bushmaster, Armalite, Magpul, LaRue, ect could fit the bill, and for cheaper than Colt.
“could” fit the bill? Maybe.
They don’t NOW.
That means they’ll have to tool up to meet the MILSPEC requirements.
Some steps and features might be cheap, but other things they don’t do, like MP the barrel and other QC testing, are expensive to set up.
And don’t confuse what you pay for a civvy AR for what the military pays for an M-4 or an M-16.
Not even close.
Colt gets $1200+ for their civvy stuff because people want to pay it.
Don’t confuse that with the true cost.
If Colt is making M-4 carbines for $400 a copy, then the others better be able to, as well.