ASMR seems like the culmination of two phenomena: one is sensory hedonism. i can imagine some corrupt Roman Emperor keeping someone around and having them rub fur because they like the sound. getting drunk and sending for them, to be taken away from whatever they were doing and forced to do this act for you. now, we don't need a human slave, we can use the internet and find people willing to do this for free, or for money.
also, it kind of seems like a natural result of the internet's emphasis on exhibitionism. there are now more famous people than ever before. fame has become almost an ambient quality. how do you stand out in a world where people are screaming for attention? a world full of people populating reality tv stars and live talent shows? how do you compete with that? what better than offering merely your subtle, mundane presence?
Slime videos, i have no idea what that is lol. tho slime was huge for 5 or so years in the late 80s/early 90s so i can understand if some people are too into slime as adults. not me tho hah.