There are not really comparable. The value of an email service is how many users it has. The value of a big database is... who knows? If Google one day decide

There are not really comparable. The value of an email service is how many users it has. The value of a big database is... who knows? If Google one day decides the content of that database is a strategic asset, they might just as well decide to shut it down to the public and continue using it internally.