If something is plausible, why isn't it accepted?

"Plausible" means:

consistent with known facts and reasonably possible.

But many plausible explanations may exist simultaneously.

Example:

Why did a king raise taxes?

Plausible explanations:

• financing war,
• paying debts,
• strengthening authority,
• funding public works.

All may be plausible.

Historians usually want evidence to determine which explanation is most convincing.

That is why plausibility alone is often insufficient.