MariaDB mysqldump lacks all data - how do I force including it?
Before posting my question I did just a few more tweaks to see what might be going wrong.  I may have stumbled into an answer.  So I posted the question anyway and I'm going to post a potential answer here in hopes that it helps the next person. 

The -d option in the second row I thought was short for --databases, but it appears to do something else.  I don't see it in the docs (https://mariadb.com/kb/en/library/mysqldump/) but when I changed that to --databases I started getting results with the INSERT INTO statements.  

So, instead of: 

/usr/bin/mysqldump -u root -p -d databasename  &gt; dbbackup-dump-$(date +\%Y-\%m-\%d).sql


Use: 

/usr/bin/mysqldump -u root -p --databases databasename  &gt; dbbackup-dump-$(date +\%Y-\%m-\%d).sql


Or (without naming the option at all): 

/usr/bin/mysqldump -u root -p databasename  &gt; dbbackup-dump-$(date +\%Y-\%m-\%d).sql