Answer by Sharbatanu Chatterjee:
Now, at independence, Pakistan was at the unique position of having two separate provinces – the East (East Bengal) having most of the fertile lands and the majority of the population, serving as the economic sustenance of the West – joined by the vast North Indian mainland.
So there were these lion's share of two large provinces – Punjab and Bengal.
West Punjab had the rich canal system cultivated across centuries by the proverbial Punjabi farmer and East Bengal had all the natural resources for running the huge jute industries. Plus it had the manual labor. And as the questioner mentioned, it had a much more homogeneous society, with a huge religious majority.
So yes, on the face of it, Pakistan had advantages
But Pakistan did not handle herself well. While they should have tried to live in a diverse way and give the Bengalis their due share, West Pakistan exploited the Eastern counterparts a lot. Prime Ministers were known to have said that the simple, effeminate Bengali was not a 'true' Muslim, were weak and were meant to be exploited.
They also defined the nation negatively, with respect to enmity against another nation only, and not on positive grounds. They did not see that economics and language served as greater identifiers rather than religion!
However, there was the entire potential of South India (and of course, also, the North Indian plains) and the gateway to Asia (North-East and East India), lost in Pakistan. Plus, the nation shared borders with fiery regions that were bound to disturb! That did undermine the potential that remained.
Then there was the lack of leaders. Jinnah passed away nine months after Gandhiji; the first Prime Minister, Liaquat Ali Khan was assassinated in 1951; the language martyrdom occurred in Dhaka in 1952, none of these bore good news for the nation. Plus, the entire system was made to revolve around one particular religion, with low tolerance and low freedom. Education, politics, sports, foreign policy, everything came to be dominated by it. Trials were made to distort and deny history. All these countered the various positives that Pakistan might have had.
The Indian nation sought to determine itself positively, worked towards consolidation of differences and had a number of leaders who worked diligently. Plus, India did have more or less good relations with Russia (an all-weather friend unlike the USA) which helped.
Concluding, while Pakistan had substantial advantages, it could not capitalize on them. India had maybe better odds, but worked charmingly in the first few years to consolidate the nation.