Solar power

We saw very few photovoltaic cells and solar hot water systems on our trip despite travelling through areas of Australia with very high solar exposure. There have been good subsidies for these but I suspect people still ask - will it pay for itself and what is the cheapest at this point in time? Are these valid questions or should we be thinking in a broader sense? We are an affluent country which adopts some new technologies like dvds, ipods and big TVs readily.