Making room for the intermittent nature of solar imposes upon the grid a large cost for backup power, adding to the levelized cost of electricity, yet this cost is never ascribed to the cost of the solar panel. The more solar you have the more idle backup power you need.
In France 70% of their power came from nuclear and they added renewables, they then need to throttle the nuclear power plants which is not an easy task, and they then make less money and require tax funded bailouts.
The fact that making money is one of the, if not the most important, considerations in this equation is the main problem with this. It simply should be a public service.
That won't automatically solve all of the other problems but many of the solutions to this problems aren't considered because they are not profitable, even though they exist. An easy example being gas turbine plants which are much easier to spin up and down as required. But perfectly meeting the needs of all people means there's no artificial scarcity and thus lower profits.
Britain pioneers alternative power storage methods, particularly pumped hydro, and invests heavily in wind farms, diversifying the grid. So, at the end of the day, they don't need backup power all that much.
Rooftop solar is routinely connected to the grid - no need to build redundant and expensive battery banks for every home, but the power is produced locally, minimizing transmission losses and strain on the power lines.
Nuclear, on its hand, is nice, but simply too expensive to build nowadays. Nuclear plants take a lot of time to pay off, so running existing plants is good, but building new ones can be a worse option overall.
Well wind farms won't help, if you need 100% reliability. Storage I figured was more expensive than nuclear after adding all the costs together, creating enough hydro for backup is extremely expensive as well.
You're essentially building a hydro power plant, water storage, pumps, and wind turbine at that point.