Load balancers are imperative for high availability in cloud environments as they distribute incoming network traffic across multiple servers to prevent any single server from becoming a bottleneck or point of failure. This ensures that if one server fails, the load balancer can redirect traffic to other operational servers. Switches and routers are critical network components, but they do not inherently provide high availability; they must be implemented in redundant pairs or clusters for this purpose. DDoS protection helps to secure the network from denial-of-service attacks but does not contribute directly to high availability.