Insight #1
The number one thing an organization can do today to help prevent the next major breach is to implement multi-factor authentication (MFA) on all things. According to research by Microsoft, MFA can block over 99.9 percent of account compromise attacks.
Insight #2
The second thing an organization can do today to help prevent the next major breach is to patch, patch, patch. Whether it is their open-source, operating systems, purchased software, etc. Every single bit of software being used in your organization will at some point have known security vulnerabilities that pave a path for malicious actors into your environment. Patching is critical.
Insight #3
The third thing an organization can do today to help prevent the next major breach is to close up your egress access from your environment. Only allowing external access to known good sources will limit an attacker's ability to more easily exfiltrate data and/or communicate to other locations. How often do you review your firewall egress rules or cloud security groups?