That leap of faith has already been taken by a massive increase in investors and companies involved in producing solar cells in just the last 2-3 years. Of all the alternative energies out there, solar is growing the most, it's not really growing - it's exploding. So I guess for the average person, if there is such a thing, this leap of faith is for now still a bit difficult, but when heavy investors put large amounts of money into it, then you have to admit, something is going on.
About payback time, even using older panels, payback time is about 7-8 years. So if you would instead put that money in a bank, you would have to calculate your earnings based on that 8 year period. So which would give you a larger earning? Putting the money you would have invested in a solar installation in a bank for 8 years, or investing it in a solar installation and not paying electricity for the next 30 years? I know in Germany and France (I think also Spain) you can sell your electricy for about 3 times what you pay for it. So you could invest in an installation just covering a third of your needs, and you would still come out even. Plus, how much would the interest rate you earn from the bank during those 8 years be eaten up by the increasing price of electricity?
The land area needed would be insignificant, I do believe a large portion of future solar installations will be private. At least, for every home owner it will make sense to have your own solar installation on your roof, which will not only provide you with cheaper electricity in the long run, but protect you from black outs (a pretty big advantage).
In any case, it won't take 10 or 15 years to see the prices on solar radically drop, and efficiencies go up, and I'm not really trying to convince the general public of anything, just giving my view of what I've read and studied about it. The investors have already been convinced and that's really all that's needed
I have come to understand with every new technology, it doesn't matter how clearly and logically you explain to people the advantages, the attitude will in most cases be: I'll wait for somebody else to try it first. Same with mobile phones, microwave ovens, the internet, and solar. We see a pretty small adoption at first, and then pretty quickly an epidemic at the point when peoples fear of the unknown is overtaken by the fear of not being left behind
