I'm in a small energy company and log 50k/s events for several million points (temperature, pressure, voltage, current, power, ...). And most of what was said is true for us but we dont pay millions per year to our vendor. Its not cheap though and will pay millions over years easy. Horizontal scaling is not what these databases do as mentioned (thinking of Wonderware, IP.21, Honeywell, PI, ...). I have some hope for AWS Timestream for cloud but still think price will be high and they only ingest near live data so nothing older than what fits in memory. Most of the open source like influx, timeseriesdb, prometheus, lack features I expect but they are getting closer.