I am not saying "Mumbai will eventually prevail" as you have presumed, I am saying Mumbai is superior right now and will stay that way, come what may! This means Mumbai is going to jump ahead further than Delhi in coming years once it's own problems are overcome.
At this point of time I am not counting Dubai as part of equation, simply because it is being developed by western coutries for their own business. In a truest sense it is an American city built in Asia with western technologies.
The corruption is existent in every city in India, Mumbai can not be an exception neither can Delhi be. Despite this brutal and bitter fact, the efficiency with which the civic bodies perform in Mumbai is far far superior to any city in India let alone Delhi. This is the true spirit of Mumbai!