what does india have that china does not?
Brahmos
Economy does not necessarily translate into military prowess.
Yes it does.
The British empire was by far the largest economy of the 19th century.
The United States was and is by far the world's largest economy since the beginning of the 20th century.
Both of these countries fostered significant economical edge over their adversaries (France and Germany). The military took care of its self later on.