[mborch]

The article states the opposite: that it's write-heavy.

The difficulty in managing time series data is that you need to do roll-ups and generally avoid doing the same work twice - that is, read the same rows over and over again.

If you're doing the same work over and over, it's always going to be slow. Don't do that! InfluxDB could presumably be built on top of PostgreSQL. It just manages the data lifecycle. But that would be a polyglot mashup project then and not something you could sell to VCs.