I don't know but I still fully take the criticism: Google Trends is not an indicator of absolute usage, but (if anything) relative usage. It's not clear which of the two parent referred to.
Those are relative positions. We can't talk about a "nosedive" from that. It may be the case, but also maybe Ruby was just the slowest growing out of a number of languages growing in popularity. We don't have enough data from there.
