The victims did not practice proper key management. The victims got hacked because of their own insecure key management, not because of any vulnerability in Bitcoin.
To claim otherwise is like claiming that because people can steal improperly secured code signing or TLS certificate private keys, all code signing and TLS certificates are inherently, fundamentally, and automatically broken, which is really just a fundamental misunderstanding of cryptography 101.
You know what every other online money transfer mechanism has? An ability to reverse transactions in the case or error or fraud. Because those things happen all of the time.
That kind of reversible payment rail can be implemented on top of a base layer like Bitcoin. Like the current banking system, with it's underlying final clearance network between banks.
Don’t have to hack crypto to steal all the crypto.