Meanwhile battery prices are dropping year over year and installed capacity is still skyrocketing. Eventually the curve will level off, but we are not to the point of diminishing returns yet. Solar and Wind + Battery is shaping up to be the dominant power source of the future. It's all down to economics. Solar cells and wind turbines are not only getting cheap to buy, but once installed they require little maintenance and no ongoing fuel costs. Batteries are similarly low maintenance and the purchase price continues to drop as economies of scale and advances in technology make them cheaper and better.
The politics argument is really "people won't let us get away with papering over horrific design and construction snafus."
https://about.bnef.com/blog/battery-pack-prices-fall-to-an-a...
If you look at PV there were similar "ah ha, costs have stopped falling!" moments in the past (mid 2000s, for example), but they didn't last long and were followed by even more dramatic cost declines. It's important not to be selective here, like climate change deniers are looking at global temperature data.
Renewables + storage certainly could provide 100% of the needs for the grid, in a properly designed system. At this point it's just a matter of quibbling over cost. Since the world could be spending upwards of a quadrillion current dollars on energy in the next century there's a hell of a lot of financial headroom to scale things up.
It's entirely reasonable to assume that some storage technologies will survive being rolled out to the scale needed to allow renewables to reach 100% penetration. After all, there are thousands of different battery chemistries, and many other non-battery storage technologies, including ones using 19th century levels of science (pumped thermal storage, for example). Your negativity requires that all fail. I think you doth whine too much.
That's why all decarbonized grids have hydro/nuclear as their main source of energy.