It worked well for Amazon because they kept it within a tight operating envelope. They used it to persist bytes on disk in multiple, smaller BDBs per node. This kept it out of trouble. They also sidestepped the concurrency and locking problems by taking care of that in the layers above. It was used more like SSTables in BigTable.

They phased out BDB before DynamoDB was launched. Some time between 2007 and 2010. By the time DynamoDB launched as a product in 2012(?), BDB was gone.