December 2011: RFC 6455 standardized WebSocket. Developers celebrated real-time communication without polling hacks. Infrastructure teams got a problem that still hasn't resolved.
HTTP assumed connections die fast. Single request, single response, close the socket. Every layer of the network stack optimized for this: firewalls tracked brief sessions, load balancers expected quick turnover, proxies aggressively timed out idle connections.
WebSocket flipped it. Now servers hold thousands of connections open indefinitely. Firewalls don't recognize the traffic pattern. Proxies kill sessions they think are stalled. Memory pools sized for transient requests exhaust under persistent load.
Fourteen years later, HTTP polling remains more common than WebSocket across the top million sites. The infrastructure never caught up. When you choose between polling and persistent connections today, you're navigating consequences of that 2011 inversion.