Hmm, considering after 2 years of shipping Druid as part of a big data analytics product, my company is moving off of Druid because of performance and stability issues, I don't think my company, at least, would consider Druid a success at all.
We are moving to Vertica, because other products in our company use that, although I'd have liked if we had gone to ClickHouse, which is faster than Vertica and Druid for our product.