They would also need aircrafts to fill them as well. And aircraft carriers are more expensive and precious ships to lose to. AC sinkers like submarines and destroyers need more investments than ACs.
Considering the present financial situation a third 65,000 tonne aircraft carrier costing billions of dollars is a luxury we cannot afford. The first priority should be
1.Nuclear submarines, both SSBN and SSN in sufficient numbers to complete our
minimum second strike capability. Armed with nuke missiles of sufficient range.
The confrontation on the border with China could take any shape in the future.
Only a robust survivable under sea nuclear weapons capability will make the
Chinese think many times before escalating tensions with India. SSBN"s to carry
and fire the SLBM's and SSN's to protect the SSBN's.
2.Conventional AIP equipped submarines to be a deterrent to the Chinese surface
and subsurface fleet. Preferably having indigenous anti ship missiles along with
Brahmos ASCM.
Nobody is stating that Aircraft Carriers are not necessary but they will be possible only after our urgent requirements for submarines are met. The US requires large mega sized aircraft carriers because they are needed thousands of kilometres away from their shores. The distance between the US and China is quite large and instead of depending on land bases in China's neighbourhood whose access is not always guaranteed, a CBG provides the US with an independent force projection capability. India is still not in a position to dream of such big power projection capabilities.
The Su30mki armed with the Brahmos missiles can cover the entire Indian Ocean region. For now they will be enough of a deterrent till we can afford big aircraft carriers.