"Everyone" except all the largest and most successful companies in the world.

The largest and mot successful companies in the world are still powered by MapReduce.

It doesn't mean it's a great technology anymore... it just means it's incredibly hard to migrate tech stacks once you're a huge and successful company.

I suppose you meant Hadoop. What have changed that makes it not a great technology any more?

"Hadoop" is never going to die. Even if it fades into the background, some vestigial remnant within Spark will use a HDFS wrapper to access S3 or something like that.

But MapReduce will eventually, finally, kick the can.

Hadoop means HDFS plus MapReduce and/or Yarn. Hadoop isn't some specific technology or tool you install, it's an ecosystem of tools.

This.

Everyone, including the largest and most successful companies in the world

Source? Or did you just pull that factoid from your imagination?

Do you have any data supporting this assertion?