I worked in the streaming area for a decade, doing research and development (see: https://scholar.google.com/citations?user=Rdf5OIYAAAAJ&hl=en). After moving on from streaming specifically and moving into the general problems in large data warehouses, I also concluded: just default to SQL for all analytics and the database lens is the best way to think about streaming for analytics.

I still do think that stream programming models are extremely interesting and powerful. But I used to think they would eventually become more mainstream as a way to elegantly program for high throughput, low latency massively parallel systems. That has not been the case, and I no longer think that it will be. People get by with the existing programming languages and models, that seems to be fine.