First, I wouldn't be so harsh on them: statistically, the probability of successful attacks increases with the size of the company, and having lived long enough I consider it a miracle that the likes of Apple and Microsoft had seen so few leaks.
Second, zero trust is a very specific concept that basically refers to not trusting networks traditionally considered as more secure, such as corporate LANs. It is definitely not a panacea, not to mention that no large company, including Google, is able to implement it in full without incurring enormous costs.
Third, whatever you do, it's extremely difficult to protect against an inside job. I'm not suggesting it was a case at all, I'm just saying it's better not to jump to conclusions too hastily.
Second, zero trust is a very specific concept that basically refers to not trusting networks traditionally considered as more secure, such as corporate LANs. It is definitely not a panacea, not to mention that no large company, including Google, is able to implement it in full without incurring enormous costs.
Third, whatever you do, it's extremely difficult to protect against an inside job. I'm not suggesting it was a case at all, I'm just saying it's better not to jump to conclusions too hastily.