The document discusses the evolution of microservices architectures over time as techniques for handling issues like failures and timeouts were developed. It describes how early approaches involved adding timeouts and circuit breakers to code. Later, approaches involved sharing state between services and client-side service discovery. Today, sidecars and service meshes have moved reliability patterns lower in the stack, standardizing protocols and allowing services to abstract away operational concerns. However, meshes also introduce new tradeoffs around portability and development cycles.