funny you should mention this, but Encyclopedia Britannica is online, free, and perhaps unsurprisingly does not often show up on SERP page 1.
You mentioned SERP and I thought - doesn't matter to me, I have a custom search for Wikipedia that I use instead of google when I know there's a wikipedia for something (I've developed really good intuition for this).
But... the same isn't true for EB, but should it? Does EB ever have anything that's not on wikipedia? Like, ever?