1911s are expensive, it's not because they're 1911s and that makes them "magical" but rather they can be either made on the loose end and not as accurate, or hand finished to be tight and accurate. Proper trigger feel, bushing/barrel fit, slide/frame fit, a tight chamber that doesn't result in misfeeds... that all takes time and costs money. If you don't want a fragile gun made of MIM parts, that will also run you more money.
It's not a 1911, any gun that would require this amount of manufacturing and finishing would cost this much to run right and last long. It's just that there's a market for high end 1911s.
People wander into a gun store, buy a 600 dollar RIA or an 800 dollar Ruger (or worse yet a Sig or Taurus) then cry all over forums about how 1911s are unreliable and finicky with ammo and if they really want to get something reliable, they need the Glock--which has a chamber so loose you could probably chamber a cartridge one caliber above and still have it fit. Worse yet, they turn amateur gunsmith and go to town with a dremel tool and try to polish and fit the parts themselves and leave a trail of Jethro-d guns in pawn stores that work sporadically at best.
OK, so not all plastic guns are bad