The real problem is un balanced regional development. No bihari or for that matter anybody wants to come and die in mumbai,if they are given a decent option to live in their neighborhood.
Mumbai developed not because of any thackeray but because of its proxmity to Harbour. It emerged as a fine metto not because of any so called nationalist politico, but because of its sea trade conveninece.
Had that happend in bihar, all those calling them quits would have gone to bihar for a livelihood.
Instead of mud sliniging, try finding out how we can have regional development in a balanced way