Flow integration only on enterprise?

I was disappointed to see that Microsoft Flow integration is only available in the Enterprise plan. 

Microsoft Flow is not just an enterprise tool.  Nor is Teams, nor is Sharepoint. Its all included in $5/mo Office365 plan, with Sign included as a standard Flow connector.  I have dozens of 5-15 user organizations using Flow/Sharepoint in some capacity (and all using Teams).  Now one of our larger clients is interested in an e-sign platform, so I was going to recommend this due to the Flow integration...  Until I saw it's limited to the enterprise plan.  They don't need a single feature from Enterprise aside from Flow integration, likely don't even need most of the features on the Business plan.

Keeping Dynamics tied to the enterprise plan makes sense, or other large enterprise focused software and ERP platforms, but not Flow.

Is there any plan to open that up to lower tier plans, or are there means to enable it for lower tier plans?

Thank you