Varying the production more often and with more amplitude decreases the efficiency and increases the maintenance costs. Maybe that's a claim by the power industries but that seems to be a legit one.
Like, this stuff is not free and to just build solar and wind capacity (whose nominal megawatts/gigawatts are inflated and capacity factor overestimated) while not caring about the grid is myopic and stupid.
Wind is especially problematic as it can fall off a cliff from one hour to the next and this may happen country-wide.
Mind you I believe I'm a pretty hard line environmentalist next to most everyone. I "hate" all those renewables because Germany has shown up what actually happens when you apply the dogmatic, simplistic no-thinking thinking. Higher costs for everyone who pays and the CO2 emissions increasing.
I believe we need new industries that can consume the intermittent surplus energy.
E.g. a place that manages a fleet of light trucks (for companies to use and for people to rent for the day), that perhaps routinely does battery swaps, where a shit ton of battery charging happens when it's the cheapest but the power use is strongly coupled to consumption goals, updated every 5 minutes and they may quickly collapse or rise back as dictated by the utility provider or some kind of regulatory structure. I'll call that a "push smartgrid".
Chemical industry with a production that can easily be scaled up/down or rather "scaled out", as per the computer jargon. Well I hope such things can be done (with "reverse fuel cells", water treatment/dessalination, or who knows what) and obviously there would be a lot of engineering and investment needed.