Except that in this particular case the aren't "unrelated" markets: Office 365 is a bundle of (enterprise) Productivity Apps and Teams is an (enterprise) Productivity app.
We also know that from a technical perspective Teams actually was a "cheaper product" because it was built on the backs of other existing parts of Office 365. It shares a ton of backend with SharePoint and it swallowed up Skype for Business/Lync. Both key products of the "bundle" before Microsoft decided on a need to compete with Slack.