The biggest problem with adaptive rate limiting is that, in many contexts, clients value predictability more than they do peak performance. Adaptive rate limits change client behavior in ways that clients can't predict or control.

Even in networking, the classic application domain of adaptive rate limits (like TCP's algorithms), core networks are built to offer predictable performance. Edge networks, like public WiFi, that offers best-effort performance with adaptive rate limits, are often met with frustration and even anger the moment those limits kick in.