Waterbeds

This has not been the least depressing day in the history of the United States. So to lighten things up a bit, what the hell was with waterbeds in the 1970s? My grandparents had one we used to sleep on when we visited and I largely remember that it was kind of fun to play on as a kid and it was not comfortable for sleeping. And then they completely disappeared. This is an entire phenomenon I cannot understand. Why were they invented? Why did people fall for them? Why did they go away? I assume that the sex on them was troublesome. Yet they seem so quintessentially 70s, precisely because it’s sex that I assume they came into fashion during that odd, odd decade.

Anyway, can some of you olds enlighten me?