Why is this downvoted? This is a pain point for us too, except we're at 500k requests/second. We're currently Datadog but everyone knows they're too expensive.
Cost management via sampling is still largely a vendor concern. Each vendor has a different solution, and while some are better than others, all can be effective at bringing costs down.
We tracé everything and first collects all spans in their trace. Then we sample the successful traces and we retain all traces ending in a failed state. This greatly reduces the need for storage.
