Development time of combat aircraft

According to the thread “Typhoon arises” below the Typhoon’s roots can be traced as long back as to 1970 (when I was born!) and that the program accelerated during the early 80s to meet the threat of the Soviet Mig-29s and Su-27s. The Typhoon is now beginning to enter production more that 15 years after the cold war, which can be considered a bit late for it´s task. Two questions come to my mind after reading this:

1) Is there a risk that current and future combat aircraft take so long time to develop that the requirements they were meant to face get outdated during the development time of the aircraft?

2) Would the Typhoon have another capability and performance if it was designed from a present specification rather than from a cold war dito?