Because you can get a quality mil-spec from Springfield for about 450?
1911's are a product of many refinements. You simply have to decide what features you can afford and then how much you want to spend.
A lot of good words exist regarding the tarus 1911, some even really like their revolvers.
Buy a Colt, Springer, or any of the more expensive weapons and you can shoot em for ten years and then sell them for close to what you paid, can't speak to the tarus resale value myself, I have never owned one of their weapons.
I am a fairly dedicated Springfield customer.