Amitava-da,
You have asked some fundamental questions in your article. First of all, why do we still want to go back to Kolkata even when we do not have a place to stay there? Secondly, why do we seek recognition from the people whom we have deserted in search of a better life? And finally, what is happiness. I'll try to share my thoughts on these issues and maybe we can attempt to search for a common answer. 

Roots have an uncanny power to attract. We may try hard to uproot ourselves from our land, people, traditions, culture, but it still keeps on pulling us back.  West Bengal and Kolkata is our roots; this is where our social and cultural being took its form. We will cease to exist as we are if Kolkata and Bengal leaves us. We need to go back again and again to replenish ourselves,  to justify and vindicate our existence. And that is why we search for recognition from our roots - maybe just to check,  are we still Bengali enough? Is our cultural being still intact and hasn't lost its purity and integrity?  It is their approval which matters to us the most, it is their recognition which makes us feel that we have not lost everything. Hence it is not the ticket sales in USA that we look forward to when we have those press conferences and shows. It is our attempt to cry out and plead, "Brothers, please do not forget us. We still exist, and we keep on our stuggle to exist as a Bengali in different parts of the World." 

As for your question on happiness, it is a question of perspective. Yudhisthir, one of the most unhappy man of Mahabharata, had his point of view. So did Duryodhan, "Sukh chaai naai Maharaaj, Joy Joy cheyechhinu - Joyee aami aaj". We, in this country, follow the Charbaak doctrine, "Rinan Kritwa Ghritang Pibet" (or something like that). Drinking ghee may have its ill effects, but who cares as long as you keep on enjoying!

 