As the person who asked, I looked into it. It seems Pop-Culture Isolation is when someone or something are a big deal within its fandom, but aren't widely recognized. Pop-Cultural Osmosis Failure is when that person or thing are widely recognized, but a character doesn't know about them.
Then what's the difference between Pop-Culture Isolation and Fan Myopia?
Pop-Culture Isolation applies to the work or person, Fan Myopia to its fans.
Fan Myopia is essentially a fallacy or mistake by someone who thinks the work they're a fan of is far more popular and/or culturally significant than it really is. It's assuming something falls into common knowledge, but really falls into Pop-Culture Isolation at best.
edited 23rd Mar '18 5:54:38 PM by AnotherDuck
Check out my fanfiction!Get it. Sub Culture Isolation would be a more fitting title though.
IP tries to find a replacement for the image on Pop-Culture Isolation and the question came up how the trope differs from Pop-Cultural Osmosis Failure. Any help?