Marriage of attraction is a gamble anyway so you might as well marry into a family that is similar to your own and make that much less of an adjustment. But the 'love marriage' as it is called is equally common in India now. But it would be interesting to do a comparison of what would work better. Marriage is hard work and it is a gamble.
As a world view Darwinism cannot of course be refuted since Faith is always has been and always will be stronger than facts.