We certainly are blessed with a geography that give us time to think and assimilate, that's about all. It doesn't give us an eternity to do so.
Bharat Mata's bountiful resources(including man power) give Hindus a chance to defend themselves. It was the vigorous defence mounted by the Hindus that slowed down the invaders for centuries and even forced them to accomodate(at least to a certain extent).
Hinduism's depiction as boa constrictor is a british artifact. Hindus actually shunned not just the invaders and their ideology(outrightly and completely) but even shunned those who were influenced by them or those who surrendered to them(willingly or foreced by circumstances). Infact, those who were lost to Hinduism in this manner were never re-assimilated(not even those who were forced by circumstances). A woman who was kidnapped and raped by the invader was effectively lost, as far as Hindu family was concerned(most of the times). The progeny of such rapes(or such connections) were not allowed into Hinduism. Such was Hindu orthodoxy.
It was not a perfect approach. But, perhaps, the Hindus of that time saw it as the only measure to keep their ideology safe from corruption.
In short, historically Hindus were not keen to assimilate any foreigner or his ideology. Further, they shunned them and any new converts(without second thoughts).
So, Bharat Mata's bounty was not used for assimilation but for mounting defence and mutinies. Again and again. Repeatedly. This process never stopped, even when the invader had already established his rule. Some group or the other raised their head and tried to challenge the invader. This forced the invaders to secure the support of the majority of population by allowing some concessions. This situation forced the invaders to take the help of local landlords, local rulers and even local Gurus. Of course, the invaders were barbarically cruel. But, they could not be as cruel as they wanted to be or as cruel as their ideology(or ideologues) exhorted them to be.
In conclusion, assimilation was never the way. Defence using Bharat Mata's bounty is.