To me your confusing technology with energy. First world countries and developing countries will still consume enormous amounts of fossil fuels for many decades.

Oil is the world’s vital source of energy and will remain so for many years to come, even under the most optimistic of assumptions about the pace and development of alternative technology. WEO 2008

All the infrastructure that supports a high tech lifestyle is fossil fuel based. The number of people who can afford to work from home is limited.

You confuse oil with all energy.

Oil is the primary source of energy for transport which in turn supports infrastructure. It can't be substituted easily, but modern society is dependant on fossil fuel, that's why I mentioned it a few times!
http://en.wikipedia.org/wiki/Hirsch_report