I cant see how any of the following attitudes could help language revival of dead and moribund languages. I think all the following also applies to conlangs that want to have a speaking community.
[Small, threatened languages that are still spoken and taught to children is another story, not address at all here].
1. Speakers must espouse and adopt the culture of the language. It’s good marketing to have some espirit de corp, but don’t let good marketing make you turn people away from learning the language because they aren’t living the way you want them to.
2. The language needs to have the prestige that it used to have. Sorry Living Latin. Your day in the sun is over. The sound of Aztec will not strike fear into the hearts of Mexican provinces like it used to. Those days are over.
3. The language can’t have loan words, calques, neologisms or area effects. I.e. no part of it can be created by later day fans. French is Latin…warped beyond recognition by intention and accident. That’s the way living languages work. Once the language is alive again, even if you manage to keep the first fans from adding loan words and loan grammar, after a generation or two or six– should we be so lucky!– the language will begin morphing into another language.
4. The language needs to be just as complex as it was at it’s height. Fans of dead languages (in the sense of those who want to speak them), are not the most talented linguists. They will grind off the sharp corners of the original language.
5. The fans and users of a dead language have to be genetic descendants of the last speakers. Is it not good enough that all humans migrated out of Africa in successive waves starting 40,000 years ago? Is it not good enough that we are all the descendants of maybe a 1000 humans that survived the massive droughts in Africa? What a racist, divisive idea that us speakers of English and French must stand back and let the descendent’s revive their language.
6. Fans and users of a dead language need to get permission from the genetic heirs of the dead language. So, how do we decide who owned Hittite? Who is the speaker for the dead languages?
A small language can’t afford to be picky about who studies the language and why.