The cybersecurity community generally believes that security breaches in recent history could have been negated. 

Research they have carried out, is suggesting that 95% of breaches from back in 2018 could have been prevented. Worryingly, they state that techniques used in 2018 are indistinguishable. 

The breach suffered by the US credit bureau Equifax in 2017 for example (personal details of 140> consumers were disclosed). was totally avoidable.