system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:  Why hasn't free, plentiful, sunlight become a part of solving our energy problems?

Why don't houses and businesses have solar panel roofs generating and adding electricity to the grid?  Why don't electric cars have roofs/hoods made from material to gather electricity and charge batteries?  Is the prohibiting reason(s) insurmountable?  Is our government(s) investing in finding solutions why?
gpt
Making solar panels takes energy. That energy costs £*x*. The solar panel makes the owner £*y* per year. If *y* << *x*, then there's no incentive to install solar panels, because they'll effectively cost you money overall unless you stay in the same place with no faults for several years. At the moment, *y* tends to be sufficiently small and *x* sufficiently large that the incentive is low.

This also holds for, for instance, your electric car idea. Good solar panels are expensive, as are batteries if you have an application where you have to store the energy for any length of time.

So overall, in the simplest case, solar panels are only viable if you envisage owning them with no problems/faults for a significant amount of time. This amount of time is decreasing as technology improves, and the cost may be further lowered by government incentives etc., but unfortunately solar panels do not automatically make you money yet.

Looking to the future, there is a lot of research into solar panel technology, and they are rapidly getting both better and cheaper. It's hard to say what the field will look like in a few years, but they may well be much more common as you suggest.