Uh, no they don't. It takes about 8-9 years. Costs are more than just raw panels. They include inverters, installation, integration, and more, IN ADDITION to solar panels, which have recently gone up in price significantly. Besides, no one puts aerospace-grade panels on houses due to high costs involved. And even if they did, the increase in efficiency would not cover for the increased purchase cost.
I challenge you to prove me wrong.