To me there are more factors than "the work is there" (at least in more developed country) to move to a big growing metropolis. An anecdotal observation I read somewhere here on HN was something like "have you logged on to tinder in a suburb of some smaller US city?".
Another big factor is the environmental one, sure if we can reduce the commute for a majority of people that would be awesome, however people will not stop moving around (restaurants, entertainment, socializing). What alternatives do we have if people are going to leave the city? Public transportation is for the most part only viable in highly dense areas. Electric car is of course going to grow their share, but medium term expanded public transportation is an extremely important part of the equation.