Gandelf's idea does have potential, it's just a long way off - for it to happen, we need bandwidth to be as reliable, available and in abundance as electricity is to our homes. Even in Denmark where broadband uptake is higher than anywhere else only 30% of internet users have broadband compared to dialup, the statistic looks even worse when you take into account those without any internet access at all!
The countries where broadband uptake is highest and that have the infrastructure in place to handle a decent application rental system are unfortunately also rather minor players (Sorry Sweden, but with a total population less than London you are

). Until the US, the UK, Germany, France, Russia, China, Japan, Canada etc. have this kind of infrastructure it's still a no go, and amusingly, these countries are the countries with some of the worse broadband infrastructures - many Americans for example are still lucky to get more than 256kbps out of their "broadband" connections.