Nobody cares about calling dibs. People will move to the product that provides the best value; a subjective assessment that is constantly being re-evaluated as conditions are ever-changing. Also, execution never looks the same even if the ideas are identical.

If you think you can build something of value for people and you care about the problem then do it or join others already doing it. If a competitor makes a mistake, learn, and if they succeed, adapt. Everything else is a distraction from solving actual problems.