Even if Heroku’s post is about polyglot programming and commodifying deployments, many of the points apply to polylgot persistence. Especially this one:
The result of all this diversity is that the safe bet, especially for large organizations, is to standardize on a single language and avoid (or even outright forbid) development in any others. Polyglot programming allows using the right tool for the job, offering substantial gains in speed and agility of development; but the switching cost of changing out the entire stack of deployment, scaling, management, and monitoring infrastructure necessary for an app written in a different language creates an intractable obstacle to reaping the benefits of polyglot.
Original title and link: Polyglot Platform ( ©myNoSQL)