I think overzealous copyright quietly killed Vaporwave. It focused on being anti-capitalist & satirical, where Vaporwave as a genre spawned out of this retrofuturistic desire to return to the 80's and 90's era of rosy nostalgia to chill electronic music like the K-Mart store tapes[0] fused with graphics from the era's games like Ecco the Dolphin[1]. The genre stood out because it was a new artform that encouraged stylistic experimentation, where listeners appreciated the nicheness and relative unpopularity.

One of the albums, Floral Shoppe[2], that helped create the movement was taken down on YouTube after receiving tens of millions of views because it directly used modulated (slowed down, reversed, autotuned, etc) samples from songs owned by Sony that fell outside the scope of fair use to the point the artist couldn't claim the album as an original work. This may have doomed it from the start to be a victim of its own relatively small success- as soon as more listeners discovered Vaporwave, it would be co-opted by the mainstream in the form of 'A E S T H E T I C S' and would cease to be the creative & original subgenre it set out to be.

[0] https://www.npr.org/2015/10/12/448059164/putting-the-k-in-mu...

[1] https://en.wikipedia.org/wiki/Chuck_Person%27s_Eccojams_Vol....

[2] https://en.wikipedia.org/wiki/Floral_Shoppe#Lisa_Frank_420/M...