Any speculation on why they'd want to do this? It seems clearly better for the consumer if wikipedia shows up at the top anytime you google a word/phrase that appears in wikipedia. Do they make money on the results that are showing up higher?
One of the reasons why Google has looked so smart is that it has leaned on Wikipedia. I have a kid in middle school and definitely one thing you learn there is you can look like an expert on any subject by consulting Wikipedia (i.e. "what calibre ammunition is used by a tommy gun?") To an extent teachers encourage it, but it can tend towards plagiarism.
The Wikipedia page is generally a safe bet for relevance but it may or may not be a quality answer.
I think today they may be like the middle school student who is learning the tricks to not look like a plagiarist.
Remember that Google search and advertising is actually in big trouble -- there is a reason why they renamed the company to Alphabet. The 90%+ market share they have in many countries is unsustainable for many cultural reasons and they have to diversify.
Could it have anything to do with Wikipedia usually being the number one result people are actually searching for for a great number of queries? And they want to distribute that traffic more democratically?
Since you asked for speculation: Wikipedia is not very well written for someone just asking a quick question to Google. Articles are overly long, and written in a boring and neutral tone.
If someone just wants to know where birds go when it rains, an article on bird habits is less relevant to them than an article that directly answers that question.
