It's interesting. I know the artist who did this.
He is truly eccentric. Not always in a bad way.
He curates a series called "Rain". The idea of "Rain" recordings is that no new sound is introduced after the first 5 minutes, but the piece stretches on for 40-75 minutes. So he is really working against development, but on purpose.
Of course, not all people like this, but the thought is to induce laziness or sleepiness.
I have written several "Rain" pieces-- here is one:http://www.archive.org/details/wh121
I am sure he did not mean to anger or frustrate people, and I always say that the good thing about music is, that there is a lot out there, and if there is stuff you don't like, for sure steer away.
Personally I don't mind the "Purr" piece, but I am more into ambient as a background for working and other things than as a front stage thing, usually.