By leasing submarines, we have achieved something that even China has not.
China built its first nuclear submarine back in the 80s, but the first deterrence patrol happened only recently, about the same time as India sent out Arihant's first deterrence patrol.
http://thediplomat.com/2015/12/china-deploys-first-nuclear-deterrence-patrol/
According toIHS Jane’s, U.S. military officials confirmed that the People’s Liberation Army Navy (PLAN) has deployed a Type-094 Jin-class nuclear-powered ballistic submarine on a nuclear deterrence patrol. If true, this represents the first time that China has deployed a sub on this kind of mission.
http://thediplomat.com/2016/10/india-quietly-commissions-deadliest-sub/
I think you guys forced yourself to go on a deterrence patrol because India was about to beat you to it.
Plus, as mentioned by the Russian ambassador, the Arihant is as stealthy as the submarine we leased. Which means, our technology is quite similar to what the US or Russians achieved back in the 90s and 2000s, and now we are aiming to build even quieter subs. Otoh, China is yet to match the Akula in stealth.
And leasing an advanced sub means so much more when you talk about it in the operational sense. We will have highly experienced crews which will come to use when our first SSN is made ready. So much time has been saved that $2B is peanuts in comparison to the priceless experience of actually operating an SSN. Not to mention, we have a full fledged CBG because of a single sub.