The statement in the sub-headline was an important point raised by Kyle Kallgren, who has a YouTube channel called "Brows Held High," where he talks about Avante-garde films, as well as Shakespeare's works.
Although I agree with his point, the problem that I find with his suggestion to translate Shakespeare into "fakey languages" is that the phenomenon of translating Shakespeare would place conlangs, or constructed languages, on the same level as real-world languages and might be at risk of trivializing the problem of trying to bring new speakers to these endangered languages. There are more speakers for conlangs than those languages. What is more, those conlangs are traditionally spoken by peoples who do not even exist in real life. If anything, they are derivative in nature, just like how the Dothraki are modeled after Central Asian and Native American tribes.
While I do not object to Shakespeare's works being translated into these fictional languages, they mainly exist for the gimmicky purpose of either drawing people into popular franchises or strengthening a devoted fan-base. The real-world languages do not exist as a niche part of an overall culture, they ARE the overall cultures in which the knowledge of the landscape revolves around. They were always in a process of being used and modified for thousands of years, whereas these conlangs are fairly recently created, and the latter reflect more off the world in which they exist than the real world.
How can you sustain endangered languages when their own devoted fans are dwindling from old age or immersion into a dominant language? This is how endangered languages can be modernized and it would disprove the notion that they are primitive and irrelevant to the 21st century. A most notable, and most appropriate, translation would be the "MacBheatha." This would make sense, considering how the play takes place in Scotland and language the Scots speak is endangered. Of course, Shakespeare's plays "Julius Caesar" and "Measure for Measure" were already translated into Scottish Gaelic. However, the overall theme of "Macbeth" is enough to connect itself to the Scottish audience, just as it is relevant to Hebrew-speakers to see their translation of "The Merchant of Venice." This identifiable means of publication may even bring new fans into Shakespeare.
As such, the connection between the audience and the translations of Shakespeare are vitally important for nation-building. How this is so is that the people that speak a "less prestigious language" are no longer reliant on the dominant language. This was what made the Swahili translations of Shakespeare's plays important for the beginnings of Tanzanian nationalism. Shakespeare translations are also important for culture-building. The Maori translation of "The Merchant of Venice" (2002) was the first Maori-language film ever produced.
An issue with making a minority language appear more autonomous that would arise, which even Klingon Hamlet has, would involve translating metaphors known not even to Modern English speakers. For example, Hamlet saying "When he himself might his quietus make with a bare bodkin" might be roughly translated into Irish Gaelic as "when he might depart for the House of Donn with a bodkin as his passage fee." Since "Quietus make" comes from the Latin phrase "Quietus est," meaning "laid to rest," it might be appropriate and more ingrained in the originality of the Irish Gaelic version, to reference the House of Donn. That, in pre-Christian Irish, mythology is the island where people go after death ruled by Donn, the god of the dead. This change might also result in "the undiscovered country from whose bourn no traveler returns" becoming "the undiscovered island from whose harbor no sailor returns."
What's interesting in the two original Scottish Gaelic translations of "Macbeth," or "MacBheatha" is the part when Lady Macbeth talks about wanting to pour spirits into her husband's ear. In two translations, the word "spirit" is replaced with spionnadh, or strength (which is also roughly translated as "spirit"), which might reference a part of Scottish Gaelic literature. This is specifically a 16th century lament by Marion Campbell mourning the execution of her husband, MacGregor of MacGregor, wishing she had spionnadh to destroy a castle. Although it shatters the original allusion of "pouring spirits" as an alcohol pun, it does create a different allusion and could open interest into the Gaelic body of literature.
However, any endangered language would still endure prejudice in the face of a dominant language culture and neglected studies into that area. This was definitely the case of Scottish Gaelic poetics when analyzing "MacBheatha," which was left unpublished since the early 1900's until fairly recently. Translating into a minority language might be seen as pointless at least and subversive at worst, so I would think that a strong argumentation could convince a lot of people to support this vital part of language revitalization.
As such, this is why I think that translating Shakespeare in endangered languages is incredibly important for language revitalization projects. I would hope that this awareness gets spread to academia as well as to other cultured YouTubers like Kyle.