The ex-Mannschaft star believes there is an unhealthy reliance on players from the nation's two top sides
Despite the two teams emerging as the finest in Europe after contesting last season's Champions League final, the former Mannschaft striker is refusing to get carried away with Germany's apparent progress.
Instead, the 45-year-old cited an expanding gulf in homegrown talent as a potential source of decline.
"Although Germany has Mario Gotze, Mesut Ozil, Thomas Muller and Toni Kroos, we lack classic strikers and fullbacks," the 1996 European championship winner highlighted to Express.de.
"In Bayern's starting lineup in the Champions League final, there were six foreign players. We felt it at the European Under-21 championships [where Germany were eliminated in the group stages].
"We must not rest now. We need to set a course in football and take massive efforts to ensure we remain competitive."
"Without Dortmund's and Bayern's input, there is considerably less talent."
Joachim Low's men had struggled in friendlies against Ecuador and the United States without the Bundesliga's leading Germany internationals.