Q1 — Passes! Cost savings is a legitimate objective. That's exactly what makes this one dangerous.
Q2 — The retrofit problem. Old buildings have no conduits; payback period often exceeds the hardware's lifespan. The budget case collapses on inspection.
Q3 — Protocol mismatch. New sensors speak modern protocols; the building runs on decades-old switchboards. Nothing to integrate with — you can collect data but not act on it.