Well the official answer was "this change isn’t driven by profit–it’s about aligning our culture and core competencies with our core customers’ needs. There are many people who use Mandrill as a (free) utilitarian infrastructure service, who are not our core customers, and who deserve to use a company that’s better set up for that in the long run."
https://blog.mailchimp.com/important-changes-to-mandrill/#co...