when the first jet planes were being developed towards the end of WWII, they were a lot more expensive than the piston engine planes of the time and therefore didnt get used much, even though there performance was much greater. 20 years later, as jet engines became more mundane, they became cheaper to produce and soon piston engines were completely obsolete. now to apply that analogy in the 21st century, the piston aircraft are non stealth fighter (f/a-18, f-15, su-27, etc.) and the jet engine is fifth generation aircraft (f-22, f-35, t-50, etc). give it some time and a combination of competition and new innovation will make 5th generation planes much easier to produce.