Modern workloads run on operating systems built for a different era. Platforms designed for single-user machines and trusted software updates now face always-online apps and sophisticated attackers. This architectural mismatch creates systemic fragility that security tools alone cannot fix.

Backward compatibility preserves old assumptions like persistent admin accounts and ambient authority. These defaults made sense when software arrived in boxes, but they amplify mistakes today. Adding security layers helps, yet the core blast radius remains large when trust is exploited.

Future systems may embrace capability-based security and ephemeral sessions. Projects like Qubes OS, Tails, and seL4 microkernel prove alternatives exist. The question isn’t whether current OSes are broken, but which inherited assumptions deserve retirement.