nprofile1qy2hwumn8ghj7un9d3shjtnyd968gmewwp6kyqpqy4nygj85ggturx4nlzzmdqunaxzsallu2cltm50f37kunx0h7jcs738atu (nprofile…8atu) Have you seen the "Content partnership hub"? Even if you disagree with the proposed solutions, the problem statements are interesting.
https://meta.wikimedia.org/wiki/Content_Partnerships_Hub/Strategic_plan
We could come up with ways to transclude non- #Wikimedia content and make it searchable, but one big problem is how to propagate corrections back to the source. A small portion of nonfree files can get the entire collection removed.
Rijksmuseum and the Smithsonian could afford to develop their own #MediaWiki extensions.