People also don't realize that too much power is just as bad as too little, worse in fact. There's always useful power sinks: pumped hydro, batteries, thermal storage, but these are not infinite.

Sure, but for all the times my electricity goes negative for half an hour, the monthly bill indicates that is vastly outweighed by all the times that it isn't.

Just have few percent of spare capacity. If suddenly it will become too sunny, you can just disconnect solar cells. If not sunny enough, then connect them back.

Obviously I'm talking only about day - the only time when solar panel output can fluctuate.

Why isn't this as easy as storing some of that excess energy in a home battery and letting the rest down in a wire into the ground? Then if it's smart enough it could only give back energy when needed.

This whole thread has way too many people who see the price as some kind of made up number that dictates how people behave, rather than recognizing that the price is a signal about the availability of useful real-world resources.

Even if the prices were strictly mandated by a centrally planned tariff that kept the same price throughout the day, every day, we'd still have the engineering challenge of how to match the energy fed into the grid versus taken out of the grid.

The prices are just a reflection of that technical issue, so solving it still needs to be done.

pay a lot of money to keep the grid stable at 50 or 60Hz or your electronics would fry

Absolutely not. Please don't make things up.

You're answering the wrong questions. I don't think people are assuming that it's simple to manage the power grid (if so, they shouldn't be...) but rather why are we locked into a system that lets business profit motive be responsible for the continued existence of the ecosystem.