Did this ever go away? 99% of programs do map/reduce all-day long.
But most people don't have "big data" in the sense of having data that requires more than a single machine to process.
Most people who think they have "big data" still don't have big data (e.g. I've done work on datasets where people insisted on using "big data" solutions when it could all easily fit in a Postgres instance with or without a columnar store with most of the working set cached in memory for a fraction of the cost).
It "went away" in the sense that more people realised they could avoid it with a few simple steps (e.g. pre-processing during ingestion), and/or fit the data they needed on fast-growing individual servers, and so the number of people continuing to use it more closer approximated the set of people who actually work on big data.
For those who actually needed it, it of course never went away.