they raised a bunch, built a market... then Amazon and Google came for them. Impala was great - I was a big advocate, but then I worked on BQ for a bit, and now Omni.... Cloudera cannot compete.
The only stumble I can identify is that they didn't support Spark. They backed the Hadoop side too hard and left Spark open to Databricks. They should have signed those guys before any other investors got in (told Matie and co "go get offers, we will add 30%).
The "only" stumble I can identify is that they're selling a last-generation solution and most companies see Hadoop as tech debt nowadays. Which is to say, it's a systemic issue with their entire product, not a tiny mistake. This is like Mesos vs Kubernetes. One got squashed.
Over time it became increasingly popular to use cloud storage instead of running HDFS. This really destroyed Cloudera's moat, because there was no operational overhead to putting your data in S3 or GCS. You just needed to run some stateless compute, and if you fucked up it didn't matter. Nowadays your "data lake" is a bunch of files in commodity storage someone else runs.
There is probably a business-school case study there for branding yourself with the problem area rather than a single solution, esp. in fast-moving domains such as tech.