I've seen non-relational databases used for things like logs, streaming data, time series, caching. I'm not saying they don't have uses. You probably know that prior to the release of Oracle in the mid-80s all databases were non-relational. Some of the "NoSQL" ideas are actually old ideas, database models that got replaced by relational databases decades ago.

Lots of big companies use Redis, MongoDB, Cassandra, DynamoDB, etc. when those tools address a business requirement better than a relational database. I have not seen NoSQL databases replacing important relational databases, I have seen NoSQL databases used for specific business requirements.

Of course big companies do a lot of software development, so you're more likely to see a variety of languages and tools in a larger organization. That may or may not validate the tools some people in the organization choose. Many large companies still use COBOL.