Faithlife classics - Some Missing from Pulpit Commentary

Mattillo

While searching for some free books this month I noticed that only some of the Pulpit commentary can be found for free but not all.  Is this by accident or by design?

https://www.logos.com/product/5768/the-pulpit-commentary 

https://ebooks.faithlife.com/search?context=product&query=pulpit%20commentary&sortBy=Relevance&limit=30&filters=status-live_Status%2Bauthor-6184_Author%2Bresourcetype-faithlifeebooksclassics_Resource%20Type&ownership=all