PipelineDB will become a standard, open-source PostgreSQL extension this year, enabling anybody using PostgreSQL to leverage continuous SQL queries in combination with all other PostgreSQL functionality.
Not for streaming analytic workloads, because PipelineDB fundamentally adds continuous queries to PostgreSQL, so data is continuously distilled and aggregated as it arrives, before it is stored, which drastically reduces the amount of data stored in PipelineDB (or soon, in PostgreSQL via the extension refactor).
But in terms of ad hoc, exploratory analytics workloads, yes - the scaling limitations would be the same, since for ad hoc, exploratory analytics PipelineDB and PostgreSQL are the same. But with that said, the processed, aggregated data that gets stored is generally much smaller than large volumes of granular data, so there is much less data to comb through with PipelineDB.
influxdb has something similar, and now so does AWS Kinesis (with their Kinesis Analytics product).