Macbook pro poor performance

I previously purchased a high end Macbook pro retina 15" which costs me 3800$ in my country after tax and to say the least i am very disatisfied by it's performance regarding gaming which was my sole purpose for this purchase . The one thing i want to know is why apple did not include at least a GTX GPU considering the enormous price tag. Instead they used a middle class cheap GPU. I mean the competition include a proper GPU with half the price,my 4 year old desktop benchmarks with significantly higher fps with the same settings used can give reference if anyone is interested. Please note that it is bootcamped with Windows 8.1 and the fps drops to almost unplayable with low settings and resolution and that is using a 2 year old game. I know it's not apple's fault and that i should have done my homework before buying and that i have been a loyal customer to apple and own every product untill now. It is just sad how a respectful company like Apple inc. became so cheap regarding hardware and yet stay this expansive. My brand new Macbook is now collecting dust in my room seeing that i can only use it for basic purposes like web browsing and so on which i can do with my 500$ Ipad or ultrabook.Thank you and would be glad to hear that someone else is facing the same situation.Just to conclude i highly recomend not buying such machine if your purpose is gaming.