Thats basically how its done in most of Europe. Price changes every 15 minutes and some smart system starting washing machines etc if a certain threshhold is reached.

Of course you can also get a hedged contract where you pay a fixed price and don't need to care about it, but you have the choice.

In places like Spain, there are different energy plans and some do include "Peak" and "Valley" price variances. Peaks are high demand, like when cooking dinner, "Valley" are the opposite.

You can adapt to these inefficies, sure, but doing so still takes more planning and effort (in this case in carefully timing one's phone charging, and in avoiding power using activities like that during non ideal times) than if there was no mismatch of availability and demand. It lessens the impact of the problem, but does not entirely remove it.

Most places in the US have peak and off peak hours with different pricing already. Certain smart thermostats can take advantage of this for running your AC and such.

Sure, but you're not getting as much output from your panels as you could in total that way, making them less efficient overall. I'm not saying you can't run a power grid on this stuff, just that the adaptations to use them in a grid effectively have costs, and those costs are not exclusive to capitalism

It's pretty easy to imagine fusion being great - but it's still just in our imaginations. No one has yet been able to build a working fusion power plant. There has been progress over the decades that people have tried, but its still a way to go yet. So although we can imagine that it could produce clean and plentiful energy, we just comparing sci-fi tech to current tech. The future reality might not be so great, and the current reality is that fusion power isn't possible at all.

To illustrate my point, lets imagine solar power from a 'theoretical' point of view, like fusion is described. Solar power uses no fuel; gets its power from sunlight. There is enough energy coming from the sun to meet the whole world's energy needs with just reality small amount of area. Solar power produces no waste biproducts... So if we just imagine the benefits of solar power, it sounds pretty much perfect. In in reality though, although solar is very good, it is still far from perfect. Construction, maintenance, and disposal of the panels are where the costs are. And so to compare to fusion, we'd need to know what it would take to build, maintain, and disposal of the fusion power plants. Currently we can't do it at all - so the costs are basically infinite. But even if our tech improves to the point where it is possible... it's hard to imagine it will be easy or cheap - especially because there will be radioactive waste. (Radioactive waste not from the fuel, but from the walls and shielding of the reactor, as it absorbs high-energy particles produced by the operation of the power plant.)

Just 20 more years of research. At least text was predicted 1990. And 2000. And 2010. And 2020. And last year.

I'm personally very excited about how it does seem to be finally making progress if slowly, but realistically, I'm less convinced that it'll be the solution to all our energy needs than many are. The physics of the process itself is very efficient, sure, but the kinds of machines needed to harness it are literally among the most expensive and complicated things built by humans, and they don't even produce net energy yet. Granted, the cost of such things should be reduced once they are industrial machinery and not exotic scientific instruments loaded with experiments, but I'd bet that the reactors themselves will still be incredibly expensive and complex (and therefore have expensive maintenance). This doesn't say good things about the actual cost of the resulting energy, even if the fuel is quite abundant. We could get abundant energy with a similarly high if not quite as much fuel efficiency with advanced fission reactors and fuel breeding, but the cost of those kinds of plants has been relatively prohibitive, and the costs of renewables has been falling. I could certainly see it possible for fusion to reach net energy, only to get used only on specialized roles or for base load power because solar panels end up being cheaper. In a sense this has already happened. It is theoretically possible, if not practically desirable, to use fusion energy in a power plant already, by detonating fusion explosives in a gigantic underground chamber full of water to heat it up, and harnessing the steam. Such ideas were considered during the cold war, but never developed, at least in part because it was calculated that they wouldn't be cost competitive compared to other power options.

not exactly but for all practical purposes might as well be

Solar power is just really inefficient nuclear fusion

Why couldn't the solar panels simply be turned off - is that not an easy solution to having too much intake?