The gigantic and unregulated power plants in the cloud

That doesn't protect against supply chain attacks.

You've totally missed the point.

No one advocated ignoring the vulnerability. I, myself, specifically stated that monitoring should be direct. Consumers should unilaterally decide where, when and how their assets are monitored.

The material point on security is that there are many, many methods of disrupting a power grid. Even when you are looking for plausible deniability, shutting down solar panels from cloud website doesn't make a list of your top 10 options. (In fact, it won't make the list in those scenarios precisely because you are looking for plausible deniability.)

Let's imagine a power grid as modern societies know them today, except all consumers monitor their solar panels themselves, and none of those consumers outsource this monitoring function to any third party foreign or domestic. Power grids can still be materially disrupted in this scenario. Especially in the case of total war. Obviously in the case of open war. And particularly in the case of cold war.

As I said, I advocate consumers disconnecting any power generation functions from networks. But if I'm in the seat coming up with post conflict, or even simply emergency recovery, operating assumptions, I'm not counting on those panels generating power. It's just irresponsible to do so. In total war EMP will knock most of that generation off line where you're luck enough not to have it eliminated entirely. In cold or open war, disruptions to distribution can and will render that generation useless. (Just ask Ukraine.)

Consumer cloud, or even personal, monitoring of solar panels does not enhance, nor does it degrade, your adversary's ability to disrupt your power grid when your adversary is at that super power level. If you believe it does, you're either not looking at the full spectrum of what you're calling "vulnerabilities" extant in the infrastructure of modern societies. Or you're underestimating the full spectrum of capabilities of modern military powers. Both, frankly, are fatal mistakes in the types of crises we're postulating.

in your later comment you mention alignment, but the reason is that there's an enormous market discontinuity between doing the "super-duper right thing" and doing the profitable thing ... due to network effect(s).

we see competition in cloud/IaaS providers because they actually need to build datacenters and networks and so there's some price floor, but when it comes to "antivirus" CrowdStrike was able to corner the market basically, and downstream from them not a lot of organizations/clients/costumers can justify having actual independent hot-spare backups (or having special procedures for updating CS signatures by only allowing it to phone home on a test env first)

the cultural symptoms you describe in so much detail are basically the froth (the economic inefficiencies afforded) on top of all the actual economic activity that's sloshing around various cost-benefit optimum points.

and it's very hard to move away from this, because in general IT is standardized enough that any business that needs some kind of IT-as-a-service will be basically forced to pick based on cost, and will basically pick whatever others in their sector pick -- and even if there are multiple providers the will usually converge on the same technology (because it's software) -- thus this minimizes the financial risk for clients/customers/downstream, even if the actual global/systemic risk increases.

I can make my computer wildly vary the amount of power it is drawing by performing different things in software. Max out the CPU and GPU load and it will instantly change from drawing ~100 watts to 500 or more.

There have been plenty of botnets in the past. Some even in the millions of computers. If such a botnet decided to make every node's power draw fluctuate per above, wouldn't this cause the same type of problem? Is there a reason we've never seen this happen despite large enough networks of hacked machines existing?

The risk is not turning all solar installations "on maximum". That happens nearly every summer day between 1 and 2pm. Automatic shutoff when the grid voltage is rising can be disabled, but more than 9 out of 10 consumer solar installations in the Netherlands deliver their maximum output on such a day for most of the summer, not running into the maximum voltage protections.

The big risk is turning them all off at the same time, while under maximum load. That will cause a brown-out that no other power generator can pick up that quickly. If the grid frequency drops far enough big parts of the grid will disconnect and cause blackouts to industry or whole areas.

It will take a lot of time to recover from that situation. Especially if it's done to the neighbouring grids as well so they can't step in to pick up some of the load.