It's not about advantages, it's about pride. You get a little extra merchandising to balance the fact that you probably have to make some sacrifices with other young players. But NT's already have good players, so there is no need to give even more incentive to train a NT guy.
I like the idea of building a NT with efficient salaries and players not bouncing from one team to the other. I think it is a good long-term plan for international success. It's just a matter of convincing the people who elect the coach, and building good relationships with NT trainers. NT training should be the opposite of farming, it should be about training the most efficient player at the cheapest price. If you do that, you help your club, and if the NT coach is one with a long-term plan, he will be interested.
"Air is beautiful, yet you cannot see it. It's soft, yet you cannot touch it. Air is a little like my brain." - Jean-Claude Van Damme