Page include parameters aren't accessible for conditional rendering

As per this post that is marked as answered but a solution is not posted.

Specifically this comment by Elissa:

It seems that the render conditions access the URL I see in my browser and not the query string in the page include.

Rob goes on to suggest the following:

Our reccomendation is to use model data to control your client side processing rather than using URL parameters. Have a parameter effect a model condition and then show the data from the model, or conditionally render based on the model.

Rob, maybe I’m slow this morning, but can you provide an example based on the following: