It's not knowable for any, but it is knowable for some. You just have to build systems that are in the some and are inherently safe. Difficult, not impossible.

Difficult often implies additional resourcing and development related costs.

Something that many companies are not willing to invest in since it will have a negative impact on the shareholder values.

Often risks are accepted, and cybersecurity insurance is used to mitigate those risks.

I agree, I just wanted to clarify that isn't mathematically impossible to make provably secure systems. It's just hard enough that it's not often done.