DeepSeek overtakes ChatGPT to top app charts

This appears to be a whole new approach to AI, requiring far less power. That's the sell and why this could potentially be so disruptive. But if it's open source, then doesn't that mean anybody can see how they did it and adjust their solution accordingly? Or is it the case that since it's been open-sourced Big Tech is at risk of being able to monopolize their AI developments? The payoff may not be as big as once believed?