Once upon a time DeFi aren't a thing, they exist but no one really understand their use case and CeFi was a big thing then, I believe once people start understanding how important decentralized is for crypto user compared to centralized projects they start going for DeFi projects, that's when DeFi Hypes begins, my answer is one can't become a threat to the other, some will still find reason to stick with centralized finance over DeFi