If it was straight ad delivery I'd agree that being closer to 10ms is achievable. But in the process of pulling in ad data, user profile data, running it through a selection algorithm that can be pretty complex for even a simple adserver, calculating and plugging in macros, gzipping, and doing that thousands of times per second per server, the latency tends to creep upward.
More/faster hardware can obviously help, but since everything's async from the browser's perspective you tend to run into higher costs and diminishing returns by pushing for the lowest latency possible.
More/faster hardware can obviously help, but since everything's async from the browser's perspective you tend to run into higher costs and diminishing returns by pushing for the lowest latency possible.