Question:

How to make Product Metrics Detail Groups visible by default for an Account in CRM online?

Answer:

Detail Groups can be set to ON by default by creating a Product Metrics record where the Product is the Detail Group itself.

Example: 

If a Detail Group is set to ON, the Rep Users can see the Products associated with that Detail Group by default in the Product Metrics section both in the Offline and Online environments.

Related Documentation:

• CRM Help Documentation: Displaying Product Metrics
• CRM Help Article: How to Set a Detail Group Tab to On in CRM Online Account Management?