If 'execution' demands a platform, what is that platform made of? People, their attitude, their thinking abilities, their education, their knowledge, their ambitions, etc.
Looked at in that context, Mumbai is a terrific platform. Seen broadly, you'll find similarities in attitudes, in education levels, in willingness to do stuff, in ambitions, etc. Just to give an example, there are countless MBAs from top b-schools in Mumbai. Just this very fact ensures that there is a certain level of thinking - which is needed for good work - already in place. It isn't a surprise that so much work happens there.
Bhilwara is another platform. One where there are such large inconsistencies in education levels, in ambitions, in attitudes, in thinking abilities, etc. How can a team ever work well to execute anything of substance?
So then the challenge of working in such a place is twofold. First, manage to create a platform. Then worry about execution.