Interesting, we’ve had a discussion going on about this over here: https://generatepress.com/forums/topic/business-model/
You just gave me an idea.
What if there was the $39.95 GP Premium which was a one time fee that you could use on unlimited of your own websites.
Then an Agency option for $xx with a yearly renewal (50% off the price), which you could use on all of your client websites. The agency option would have the ability to add your license key to wp-config.php, and would also white label GP Premium so the client couldn’t see the “Appearance > GeneratePress” page.
I’m just spitballing here, but it seems like the above would kind of offer a solution to what you’re talking about and what we were talking about in the Business Model thread.
Would definitely be interested in hearing what people thought of something like this 🙂