First, it is an impossibility for everyone to put up panels. There is a large percentage of people who do not have the space to install panels (i.e. someone living on the 2nd floor of 3 story condo, renters) and just having space does not mean you can produce enough power even to cover your own power needs. This is even more true for businesses.

Second, I stated clearly that the current systems works OK, but scaling will require new solutions. Those solutions will need to be technical as well as legislative.

It looks promising that in 4-6 years solid state batteries will enter the market. Current Li-ion batteries get about 20% cheaper each year. That will change the calculations as well.

Right now (if we could find an installer) my wife and I would install panels to cover our needs and MAYBE sell any small excess back to the city of Vienna. "Maybe" because the extra hardware to sell back to the grid is not free. We could instead put a battery pack in our cellar. In five years if battery technology advances as it has been, it might be a better idea to buy more batteries that can hold a charge longer and never sell back to the grid, instead using the batteries during peak power times to reduce (or hopefully eliminate) our need to buy any power at all from the grid.

My point here is that this whole issue of "selling back to the grid" is a small problem that may get even smaller as time goes on and technology improves.