Capturing GB means going through POK and getting into full blown war with porkis and Chinkis.
Do Indian people have the stomach for the fall out? It will not only be a few of our boys lost - it can possibly be hundreds lost, billions of $ in cost, potential severe damage to our infrastructure at at least in western parts of India, likely economic sanction resulting in economic depression.
The cost is not worth supporting some groups in Afghanistan. Not yet.
In may be 5 years, India would gain the economic might coupled with military muscles to pull through that. But, not yet.
The day our military becomes so powerful that it can smash Porki defences within a few days, especially in mountains of PoK and GB, will be the day we can venture to do such. Because India can't afford to get into a protracted war because failing economy would do more harm to Hindustan than any threat porkis or Talibs poses. Ours is not a nation where opposition too thinks good for the nation. The moment we engage in the venture, the opposition would start crying bloody murder and when the economic costs trickle down to the masses, the mass will go against the venture.
So, our military build up needs to reach to the point where Porkis become so bloody insignificant that it is only Chinkis we would have to worry when we will be going into PoK and GB. The current pace is good so long the procurement processes aren't protracted needlessly.