I've similarly spent a decade in the streaming space, started a stream processing startup, built three streaming platforms at various large companies... and I basically agree.

Streaming always felt like it was about to happen, and it kept not happening, in a year of the linux desktop sort of way. I (and others, who also optimistically started stream processing startups) thought it was a technology problem but ultimately it's a demand problem: very few companies actually need low latency processing. And continuously running, stateful systems are inherently more complex to operate and evolve compared to batch systems.

Now that relatively low-latency ingest into warehouses and datalakes is easily achieved, it's really hard to make the argument to invest in complicated streaming systems.

That said, it still feels like we've landed in a suboptimal spot. Stream processors (in particular, those following the dataflow model) solve two problems that are hard in batch systems:

1. Determining and signaling completeness for a time period (when have I likely received all of the data for 12:01pm, such that I can now safely process it)

2. Avoiding expensive recomputations for periodic queries

I do think long term we'll see some amount of streaming influence moving back into the batch systems, particularly as object storage gives us the ability to run stateful workloads with less operational headache.

(If anyone else finds these problems interesting, I'm hiring for my stream processing team at Cloudflare. Email in my profile)