For China to catch up to Russia, 20 years is again wishful thinking. The only area where Russia and Ukraine has an edge is jet engines. My personal estimate, in around 7-10 years max China will be able to mass produce engines as good or better than Russians.
India's own defense industry is not in the same league where air superiority fighters are concerned, so lets keep that out of the discussion.
The reason why I bring up this issue is to point out, which you have agreed with, is that India saw early on that their option of utilizing Russian weapons to keep balance with Chinese conventional weapons will no longer remain an option. FGFA will probably be the last major program between India and Russia. And I saw analysis that either Rafale or FGFA may not be adequate to counter a fully developed J-20, which may turn out to be superior to both by the time they enter service around 2020.
What this means is that loosing this Russia option to balance Chinese weapons, India will no longer have the ability to pursue non-alignment and will have to embrace the West, if they want to get the best weapons they have to offer, such as F-35.
For the above reason, I believe in about 5 years India will have no choice but to become a partner of Western security structure and thus become a major non-NATO ally like Japan.
You may find the above relevant and interesting. There is no marauding herds waiting to assault you, its just that you may be forced to choose sides as a consequence of China's technological advance. No more luxury of non-alignment.