Yes, because for a given manufacturing process the density...
Agreed, if you keep doing the same thing you get no improvement. Instead of a simple metal grid, you can use Fresnel lenses, or even ring-shaped metallic nanocavity arrays. Lets not get away from the fact however that the amount of energy needed is still only a very small percentage of what reaches the surface anyway.
Batteries offer a few minutes of power. ... Gas installations are still necessary and will be for the foreseeable future.
Battery capacity is a function of how big and how they are configured. Musk math (so some hyperbole may be present) is that the scope of battery manufacturing needed to meet global demand for the electricity grid is on the order of present automobile manufacturing. The point being that is it big, but not something outside of our capability.
Let us not forget that there are a lot of battery storage alternatives to lithium-ion. The interesting ones I see are salt water based, and potassium air. They both rely on abundant natural resources, and recycling would be easier (in the case of the salt water ones, you could literally mix the components and get sea water which is easy to dispose of; potassium is the 7th most abundant element in the earths crust). Both those technologies offer very deep discharging: 80% in the salt water ones, and 90% in potassium air (by comparison lead acid is 50% and lithium ion is 70%). The disadvantage to salt water is relatively slow charge/discharge times (10 hour/20 hour in current production batteries), but that could be combined with other technologies to smooth out the overall rate. Salt water also cannot operate in very cold temperatures (about -5C), so would need to be housed in buildings or warming blankets in northern climates. Salt water appears to have similar weight storage densities to lithium ion, and potassium air seems to be far better by a factor of about 3.