> I like to think there is no curve only fashion.

Exactly! For instance, we had pull-based monitoring 20 years ago (Zabbix et al), but we abandoned it because it scaled poorly, favoring push-based agents (for InfluxDB, KairosDB etc). Now Prometheus is all the rage, yet we’re hitting the exact same scaling walls these systems had before. In a few years, we’ll rediscover push agents and call them the best thing since sliced bread.