Blockchain is one of the most secure and open-access methods of data storage ever invented, and this method is considered to be impossible to ever change, even to hack.
Anything being programmed is hackable; don't say it's not hackable. Security measures could be very high, but once a bug is discovered that could be used to access any smart contract, the next thing is exploitation.
But why Meta?
Blockchain is a well secured technology that is reliable as long as the protocol is strictly adhered to, as you've said, there must not be any chances of creating any vulnerability on the technology to allow the introduction of bugs which may cause the protocol under attack, since it's a technology that was programmed, we can choose not make it hackable or allow others invade the network and hack it through any slight chances for vulnerability, i was also considering if this discussion has another thing to talk about related to the forum but to my surprise, the title already carries the entire contents to OP post on this thread, he should move the thread to beginners and help despite blockchain technology discussion had been made several times.