Re: Car-achii......
i dunno how much the minibus people had to do with double sawari. but that'll start a discussion with no real conclusion so i wont address that.
my parents used to use the rail service in karachi. The problem was that stations are quite far apart, it is much more convenient to get the bus from where you lived instead of walking a couple of kilometers from each rail station. So not only is it a matter of efficiency, but spread. Getting a well spread out rail network in a city like Karachi is not easy, so maybe the minibuses didnt help, but that might not be the dominant reason.
the reason they were adopted by people was that they filled a need. the double sawari etc afaik is mid-90s stuff... the rail was long dead by then.