Earlier quoted context omitted.
From what I understand, the desire for instantaneous transactions is has an inverse relation with how much money you have. Poorer countries are generally way, way ahead in mobile banking, because in a rich country you are supposed to keep around a month's salary in all your accounts, making transfers less urgent.
The way I understand it, it's a coordination issue - the bigger a market is, the longer it takes for a big change to be adopted by everyone. Plausible stories are easy to make up. Lots of countries - probably most - with higher GDP per capita than the US have lower latency banking. The US has a large proportion of people who are worse off than the equivalents in many poorer countries, too.
Many places leapfrogged directly to mobile phones (featurephones mostly) because there were little to no power and/or landline wiring present (and attempts at getting such infrastructure in place got disrupted by people stealing the wiring and selling it as scrap copper).