What's the logic behind Tier 3 determination?

New user here, attempting to get my head around the paywall decisions.

Active Directory is shown as having a Tier 3 Enterprise requirement but I wonder if that is oversimplifying the flavors of AD. Maybe this is meant for on-premises rather Azure cloud?

There is a notable lack of modules for Azure and Azure Dev Ops.

Amazon S3, Redshift, Lambda, SES, and SNS are available without jumping to Enterprise. A level playing field would be nice.