Quality costs, regardless of design. Yes, the cost of the AR series design is fully amortized and it's more or less in the public domain. Still high quality AR's are pricy guns.
The Navy Seals use the Knight's Armament SR-25, the final perfection of the AR-10 design that Eugene Stoner himself worked on until shortly before his death.
Over here at Impact Guns they have SR-25s between $6,200 and $9,000. These aren't fancied up builder specials, these are box stock Knight "AR-10s" that are full milspec quality for the Navy.
The DPMS AR-10 cost $1,000. The Armalites run to about $2,000. Surplus FN-FALs cost $1000 in 1985, 25 years ago. FN no longer makes them, so used examples fetch $3,000 to $5,000 depending on variant and condition. According to this inflation calculator $1000 1985 dollars is $1975 2008 dollars.
Given all these factors I don't think the SCAR is overpriced, though it may be out of reach for many people. At least some of our elite units are equipping with them.
The box fed .308 semi-automatic magazine is the choice of the thinking civilian for self defense. So far the FN-FAL is the still the best of the bunch*. The SCAR looks to be the rifle most likely to take the title from the FAL, from everything I've seen.
I'm looking forward to getting my hands on one to put it through its paces sometime in the future.
*Apologies to the M-14/M-1A fans.
For civilian use, and for some special ops use, the .308 is still the best choice. That's why besides the .223 we still issue a variety of .308 rifles, including AR-10s and SR-25's as well as Remington Model 700s.
Strangely the FN-FAL 20 round magazine is almost indestructable. You can stand on an empty one without damaging it. Pre-ban you could but them all day for $7 a piece. Looking at the SCAR it appears to me that it may use the FAL magazine. (That would make sense, both guns are FN designs. Why redesign what wasn't broken.) It's odd that 40 years into it's time as the rifle of the worlds most powerful military the AR-15 magazine is still an issue.
One of the main problems with the FN was that it didn't have any provision for mounting optics. Another approach to upgrading the FN design has been taken by DSArms who has many variations, including "flat top" designs that make mounting scopes a lot easier. Most go for about $1800.
Armalite makes AR-10s, they are the first of the reproduction makers to re-introduce the AR-10. They have both flat top and iron site/ carrying handle models. My favorite of theirs is their clone of the original AR-10, which was only used by Portugal and their clients in Africa - Mozambique and Angola. It has the charging handle inside the carrying handle, another idea that the Army did away with when productizing the design. (Along with reducing it to varmint caliber.)
This is close to the way Eugene Stoner originally designed the gun.
DMPS Panther Arms is the other viable source for civilian .308 caliber AR-10s.
Happy holidays! Stay armed! Stay safe!