no it's not a threat. Defi is an alternative choice for those who do not trust the current financial system. The presence or absence of DEFI will not affect the existence of a centralized financial system. then whether defi is the financial future? I do not think so. because completely trusting the defi is a mistake. Decentralization means that it cannot be controlled and it is very fragile. so the existing masintream financial system will remain in the future. because we can never fully trust Defi.