Indian scientists are not ponga pandits to make overweight missiles which could simply be matched by other missiles of lower weight. Akash is a RAMJET which means that it has much higher endurance than AMRAAM or other rocket motor missile. AMRAAM might have range of 20km or so at best whereas the 30 km is the maximum distance for easier target like cruise missile. Akash has NEZ of 30km against highly maneuverable planes and can chase them down if the planes are within that range when being fired.this is a working proven system, mate. supposed to believe is not the point. it has worked in simulations and actual tests. now take your 200kgVs720kg argument and turn it around on it's head. quite obviously it will involve a booster of some sort. even if you add that weight to AMRAAM weight, the advantages of the 200+boosterVs720 becomes quite obvious and also quite obvious why it is preferred. cause it's better.
what if the chinese develop a radar jammer which targets the akash batteries, specifically their operating band ? won't having this US system save the day ? rather than lose it moan and then realise that we should have another one in stock ? i would. air defence of Delhi during war is going to save the whole defence apparatus of india. Delhi isn't any other location in India defence wise. India can raise another Gurgaon or bangalore today. It can't raise a Delhi so easily.
Next, jamming of only Akash radar is not meaningful. Radars have wide operating band and can change frequency within it. You are only arguing for the sake of arguing. Moreover, other shorter range QRSAM will also be kept in addition to Akash. In BMD role, two layers of PAD and AAD will be kept. Additional layers of S300 or S400 will also be added. With all these protection, what is NASAMS doing?