[gkst]

I doubt that Google prioritizes Wikipedia deliberately. Wikipedia has tons of backlinks, authority, trust, typically a high text to html ratio, probably a low bounce rate. Moreover, it is fast, works well on mobile and on and on. It's is just a very well done and useful site for users and search engines.

[kowdermeister]

My thoughts as well. They don't need special treatment to be in the top 3.

[allendoerfer]

Wikipedia being ranked high is even an indicator for SEOs that an affiliate niche is not very competitive.