JJK is one thing but I bet Tokyo Revengers will be forgotten after 2 - 3 years. Well, that's even the case with JJK.
Such mangas will fade away. But what's about mangas like Death Note or FMA? They actually have a real important value when it comes to the anime/manga community. Let alone mangas like Naruto and Bleach - those "popular" mangas will never reach their levels of importance.
I read or watched lots of anime/manga. People thought this one will surpass One Piece, it never did.
Funnily enough, of all the new mangas, Demon Slayer is the one which I still greatly remember until now because the characters aren't only well written, you feel connected to them. The moons, Tanjiro as the main character, Zenitsu, etc. Who was the protagonist of JJK again?
Important characters like Gojo exist - but a few are not really enough if 90% of "important" characters are easily forgotten.
I'm not saying these anime or manga are bad. If I watched or read them again, it sure would be fun - however, that's it honestly.
One Piece is objectively the most well-known manga, regardless of how shitty the current arc is.