Root cause analysis delivers great value by determining if the problem can
be solved. Sometimes, even if it's abundantly clear that the problem should be solved, the solution falls outside the realm of things that are possible. In this case, obviously, you shouldn't try to solve it.
Sometimes, the root causes are entirely beyond the business's control. These causes include
such uncontrollable realities as market pressures, actions by competitors, legal or political realities, economic volatility, etc. Rather than waste time and money looking for solutions to these problems, it's better to find ways to mitigate their impact or work around them. Don't waste resources on the impossible.
Sometimes, the root causes are controllable, but there's so much resistance to eliminating them that any efforts to solve them are destined to fail, and may even stand in the way of the project reaching its goals. In these situations, it's essential to involve the project leaders and sponsors in determining the next steps. The project sponsor may have sufficient influence on other parts of the organization to reduce the resistance, or to scrap the solution and adjust the scope of the project accordingly.