Even if we were to try considering interactions we would fail. Like the weather, and other topics in the complex systems domain, software is sensitive to initial conditions. A small change in input (change in data or code) creates a large change in output.
We generally accept the upper bound on weather forecast to be 7 days and even then we might bring an umbrella just in case. Forecasting software many months into the future is futile - if taken at face value. Used as a general guideline it is usually ok.
A paradigm shift is needed. Both inside and outside the industry. Software is not industrial construction, hence the same logic (project management) do not apply.
Software is creation, conduction and orchestration. Not production or manufacturing. We are not teams of architect, builders and operators. We are musicians in a orchestra.
How long does it take to write a symphony?