The "three pillars" framing of observability quietly became three products, three bills, and three places to look during an outage. The pillars were never meant to be walls.
The cost of context-switching
When metrics, logs, and traces live in separate systems, the expensive operation is not storage — it is the human jumping between them under pressure, re-typing the same filter three times.
Correlation as a first-class operation
Unified telemetry makes "show me the logs for this exact slow trace" a single join, not a manual hunt. That is where MTTR actually drops.
One timeline, one price
Three tools also means three bills, three retention policies, and three on-call runbooks. Collapsing logs, metrics, and traces onto one timeline is not just faster to query — it is one system to reason about, budget for, and teach a new hire. The savings show up in the invoice and in the calendar.