Prometheus is a (rare) recent example of a significant, thriving open-source project that is community-based. Not quite as broad in scope as something like Elasticsearch though.
Depending on what "community-driven" means, I'd like to add Python, Blender, Jupyter, Django ...
I'd say "thriving community-based open source projects" are rare in the sense that most open source projects don't thrive (especially if you count every open-licensed repository on github), but there are tons of examples.
I'd say "thriving community-based open source projects" are rare in the sense that most open source projects don't thrive (especially if you count every open-licensed repository on github), but there are tons of examples.