Energy payback time is a different concept than money payback time. Investors are interested in the latter, First one is a rudimentary requirement for long term feasibility without subsidies.

Also, global solar is going up like crazy. Global sustained growth rate of around 40% is crazy fast. If that keeps on for a bit more than ten years, 100% of current global electricity demand is covered by solar. Just for comparison, there exists no two subsequent full years of iPhone production where Apple would have managed to achieve 100% growth.