I see this posted a lot as if this is an issue with capitalism. No, this is what happens when you have to deal with maintaining the power grid using capitalism as a tool.
Power generation needs to match consumption. Always constantly the power grid must be balanced. If you consume more than you can generate, you get a blackout. If you generate more than you use, something catches fire.
Renewables generate power on their own schedule. This is a problem that can be solved with storage. But storage is expensive and takes time to construct.
Negative prices are done to try and balance the load. Its not a problem, its an opportunity. If you want to do something that needs a lot of power, you can make money by consuming energy when more consumption is needed. And if you buy a utility scale battery, you can make money when both charging and discharging it if you schedule it right.
That's not renewables being a problem, that's just what happens when the engineering realities of the power grid come into contact with the economic system that is prevalent for now.