I wouldn't call solar energy a "luxury", more like an invesment. Its true, right now the initial investment is high with a medium term payoff (many years, even with government subsidies). Solar panel prices are coming down, but most people will still have to hire the labor to install the system, and labor costs don't drop by large factors. So the barrier is for people with insufficient means to make the initial capital investment.
There are some clever finanacing schemes. For new construction, a solar photovoltaic system would not add a large fractoin to the price of the house, and since most buyer take out a 30 year loan, the extra in the monthly payment would be small, less than the savings in the utility bill, so the decision to go solar would start paying for itself on day one! The City of Berkeley is discussing the idea that the City pays (loans) for the solar installation, and it would get its money back by utility fees normally collect by the electric company.
Solar panel sales are increasing by more that 50% per year, so i do expect the economics to improve in the next 5 years. I already installed solar panels on my roof, and don't pay much for electricity (they stll charge for the connection to the grid).
Cheers
John Vallerga