Some of the contention is directly in your choice of words: "should" and "plan". So far no Proof of Stake system has made it into the wild. There's a lot of talk about Proof of Stake, a lot of planning, a number of "almost attempts", but still no one running it at a big scale. It's trapped in "Soon™" the way Ethereum has talked about it, for years now. That's certainly an easy form of contention when even the biggest group talking about Proof of Stake have remained slow to pull the trigger.
First I've heard of it, so equating "wild/at scale" to include general mainstream acceptance/word of mouth (or at least the impression of such to the average HN reader such as myself), the short answer right now is, based on my personal barometer: no.
I will look into it later, and decide on the longer answer if it would meet characteristics that I would ascribe to "in the wild" or "at scale" given a deeper understanding of what it has accomplished to date.
