Yousuf has a point. Generally speaking, there is more attention on the short form of the game in pak than in other cricket playing countries. Having said that, I feel the answer lies in the horses for courses theory: just like jeevaypak said eariler, why not simply have 2 or 3 seperate teams, one for each format of the game?
i remember many teams in the past used to have seperate teams for tests and odis. Why can't pak do the same? Why not seperate teams for tests, odi's and T20s? This is the easiest and best solution. Have the most qualified player for each format specialize in what they excel at.
If T20 pays more money then people definitely move towards T20, more players will try to qualify for T20 than Tests.