As we grow towards a universal platform and solving issues, Defi would be one of the most secure way to handle our finance, fast, efficient and secure.
What universal platform? DeFi gives no guarantee of being the "most secure way". Decentralizing finance is an idea to allow access to finanical tools without central parties. Security has got nothing to do with it being decentralized. Its security will only be as good as the underlying protocols and the intelligence/ expertise of its devs.
From the host of attacks, it is clear that the ethereum based platforms are inherently insecure due to a multitude of possible bugs. This one was an exploit of the ERC-777 standard btw. If you need security, all these "devs" and "teams" should stop playing with toys that sound exciting and focus on development using bitcoin, the safest network there'll ever be.
--snip--security like cold wallet storage and multi-sig function on the parts of the team members.
In such exploits, security is breached not because of not following basic things like cold-wallet or multi-sig. These are breaches due to inherent weaknesses of the ethereum platform. Since the DAO Hack, it has been shown numerous times that Ethereum based entities lose money due to code issues. How can people just put in millions on these is beyond understanding. Novelty and the greed i suppose.