To this day Kalbadevi is a Gujju, Marwari area. They are so prosprous today who would have imagined that thier ancesters had come to Kalbadevi to escape a Famine

I disagree.The British had invited prosperous Gujarati/ Parsi and Marwari business in their new presidency town of Bombay. This is certainly not to say that all who came here were prosperous but they had not come here to escape famine.Traditionally in the Indian sub-continent the business communities of north-western (Gujarat . Rajasthan and Sindh)India are the most enterprising. Geography indeed plays an important role in that as all these three provinces are predominantly arid.Just as the World's first traders were the Arabs because they could produce precious little. The story of prosperity of the Gujarati and Marwari businessmen is interlinked with the expansion of the British empire.The British needed traders wherever they went in the Indian sub-continent.All the three presidency towns (Bombay, Calcuta and Madras) founded by the British have a considerable presence of them even today and they rule the business scene.The Gujaratis went even further and established themselves in British ruled portions of Africa as well.The security provided under the erstwhile kingdoms was a catlyst as that helped them to relocate unlike prosperous provinces like UP,Bengal and Bihar which were plundered beyond recognition by earlier the Mughals and later the British.In fact Zamidaris were auctioned by the British in Bihar and parts of Bengal.These provinces had islands of prosperous kingdoms between predominantly British territory.Such was the scale of devastation that there was practically no nobility left.Eventually the British had to create Rai Bahadurs and Rai Sahibs and Rajahs.Quite a few were accoded large landed gentry status for their support in the great mutiny of 1857.(which is now also called the 1st war of India's independence).

Trade always received patronage from Royalty as it was the main source of revenue for the state, finance for expeditions and source for ostentatious consumption. So the trading community was always the darling of rulers except when in Europe the traders engendered capitalism which directly challenged the feudal rule and social order.

The British were managing their supply chain too through encouragement to local trading communities. Shivaji in the 17th century too encouraged the trading ommunity of Gujrathis in Surat who had fallen foul of the British dominance there; to move to Maharashtra. THis community later spread into Maharshtra starting with the medieval trade route in Chaul and Mahad in Konkan.

Bombay was a capitalist city created to serve the Imperialist. Parsis and Khoja Muslims were among its early urban settlers and most of them indulged in Opium Smuggling with Patronage of its Imperial Masters. ... you can read the book "Opium City" for further refrence

To add another complication, there is evidence that a lot of migration to Bombay happened as a defense against gorilla attacks and plunder parties by various groups including the Marathas. Now don't beat me up for saying the unspeakable. :D

A lot of migration to Mumbai? At what time period? What evidence?