Not op but would like to comment on this:
SSB is great; I'm not sure if others would agree, but while I think it has a lot of problems, none seem inherent (i.e. while they mightn't necessarily be easy to fix, they wouldn't involve any major architectural overhauls or scratch rethinks; what's there is conceptually sound).
The main issue for me is performance and resource usage, which is tricky since a lot of the traditional solutions to perf/resource challenges are cloud-based, which would erode ssb's value. Thinking about SSB on older recycled or embedded systems, etc. is hard.
The other is NIH; this is definitely something I feel the community is acutely aware of however; I recall seeing discussions of parallel implementations in Kafka, etc. years ago. I haven't kept up with recent development though.
