One of the reasons Mitsubishi is faltering lately is because they decided to develop a WRC car with the Evo VII.
The death of Henri Toivonen in 1986 meant that Group B and Group S cars were banned instantly, and a new Group A was introduced. While the safety of Group A was second to none, the sport was also a little boring. But as manufacturers got into it, cars like the 555 Impreza and the Lancer came into their own. As they started to push the boundaries of development, the FIA decided that it was time to introduce a new formula - WRC.
Pretty soon every team had built a WRC car and were racing it. With one exception - Mitsubishi. Every Lancer from the original Evo to the Evo VI was classified as a Group A car compared to the WRC. Mitsubishi saw a slight loophole in the rules and exploited it perfectly - under Group A laws they were able to make more modifications to the car over the year than WRC cars, they could be lighter and there were other rules that weren't as strict. Every other team jumped at the opportunity to develop a new WRC car feeling the Group A cars were not worth it, but Mitsubishi alone saw that they could build the Evos and still be competitive. So, essentially, all those World Rally Championships were not won by a WRC car. They were won by a Group A car.
It's the same as when Audi introduced the 4WD Quatto back in the '80s. No other team saw the potential of 4WD and when Audi asked would they mind if a 4WD car was run, the others all laughed because the only 4WD car Audi had made was a 75bhp truck-like vehicle for use in the military. But Adi introduced the Quattro, blew away the competition and made history.