Products that identify a conflict, resolve it, and thus release potential energy successfully often have a feel of inevitability about them; they are ideas that make you think, 'Of course!' It's not until the answer appears that the question seems obvious. Sometimes the product is an advance in technology, like the cell phone. Other times, it's merely a new combination of existing technology.
'Swiping your credit card right at the gas pump? Why didn't someone think of this before?'
Of course, being ahead of the curve technologically is no guarantee of success. The Apple Newton didn't catch on, but the Palm Pilot became ubiquitous. It's all about striking the societal psyche at the right moment.
Once, the idea that people would pay for water seemed absurd; enter the fitness boom and concerns about municipal water. Before the ascendancy of Starbucks, a four-dollar cup of coffee was a ridiculous notion. When ATMs were introduced, the prevailing wisdom said that people wouldn't trust a machine to do their banking.