It is unfortunately true that intermittent sources of power generation subtract from grid stability. Texas (ERCOT region) had a huge incident back in 2019 with rates skyrocketing to $9/KWh for over 90 minutes. Many attributed this to an over-reliance on wind generation.

No, that would be using solar as a scapegoat for bad planning.

What do you mean by bad planning. Are you talking about planning that is flexible and responsive to pick up the slack. For example, a high demand day that is cloudy and not windy?

I am talking about designing a grid to be robust, and has enough spare capacity to handle difficulties without failing catastrophically.

For critical infrastructure, you design for worst-case scenarios, inflate the safety margins, and make backup plans (like a plan to gracefully degrade service).

Failing this and cutting corners is what I would call bad planning.