Not sure what you mean by "absorption" of Mandrill, to wit: Mandrill was always an in-house product of the mailchimp company, they just had it as a separate product vertical. My impression is that the effort to maintain the product wasn't financially viable and so it's effectively still run as a courtesy to mailchimp customers, but it's basically on life support.

As for where to go -- Sendgrid and Sparkpost are popular offerings in the same space:

  http://blog.mandrill.com/important-changes-to-mandrill.html
  https://sendgrid.com/blog/how-to-migrate-from-mandrill-to-sendgrid/
  https://www.sparkpost.com/migration-guides/mandrill/

[big fat disclaimer -- I work at sparkpost, but trying to provide a neutral helpful comment -- hopefully I've done that :D]