Discussing the evolution of cybersecurity, the speaker reflects on how technology has advanced over the decades leading to increased cyber threats. Initially, closed systems with limited access like mainframes were common, but with the introduction of networking, including LANs and Wi-Fi, the attack surface expanded. The shift from centralized servers to distributed devices and the rise of applications accessing backend servers created additional vulnerabilities. The speaker emphasizes the importance of cybersecurity due to the vast number of potential attackers, many of whom are skilled. Cybersecurity entails protecting systems, networks, and applications from digital attacks due to the high costs associated with compromises.