I'm not an investor or someone whose job is to track companies and their tech stacks (I can't list them here), but there are many, many medium and small startup

I'm not an investor or someone whose job is to track companies and their tech stacks (I can't list them here), but there are many, many medium and small startups that adopted Clojure not too long ago (especially in European countries). Pitch.com was founded in 2018, Clubhouse.io, Metabase in 2014; Ladder in 2015; Flexiana, Watchful.io in 2016. Mind that these are official dates when the companies were established, some took at least a year, two, or even more to get going. Your case is anecdotal, and I bet it has little to do with Clojure itself and primarily is driven by some other factors. There are tons of talks from various Clojure conferences on Youtube, where the speakers come from different startups.