Is it a sign, or do you have proof?
An early sign is incredibly valuable because you can still do a lot if you are able to make a good judgment based on your interpretation of it.
Along the way to a point of achieving proof, you will no doubt encounter a lot of early signs or signals of change, which will suggest that a condition of ultimate proof is on its way.
Most people can see that in hindsight, very few get that right with foresight.
An early sign is incredibly valuable, because you still have time to make strategic moves if you are able to make a good judgment based on your interpretation of it; once you have proof, it's too late.
Your agency to act has left you.
The trick to achieving a competative advantage is being able to successfully select and read the feint signs of change on the horizon, and then knowing when to act.
Feint signs are not facts, they are not certain, they are not hard evidence. Working successfully with signs of change takes a very different kind of mind- and skillset to one that is accostomed to working with facts.
If you are waiting for proof, it might be too late.