I am sure migrants from the North would have learnt Marathi had it been a good language. Look at Biharis in Kolkata, they learn Bengali. The reason is clear, Bengali is a language with a high culture. While Marathi is a language with a very Dehati sounds, and inferior culture. Moreover, Marathis wear black topi, geeky eye-glasses, black bund-gala coat, dhoti, and always carry an umbrella, even during summers. Thus their dress sense is also very Dehati. If Marathis had things their way, each male in India will look like Gopal Krishna Gokhle or Lokmanya Tilak! Thus it is an indisputable fact that Marathi culture is an inferior culture which very few outsiders can like.