There's a major difference that makes Wikipedia fundamentally different than encyclopedias. Britannica was written primarily by experts ranging from Albert Einstein to Isaac Asimov, and everybody in between. And these writers would offer their own perspectives, insights, and expertise. It was a rich primary source.

Wikipedia, by contrast, is not a primary source, and writers are supposed to do little more than paraphrase reliable sources. This is a good idea in theory to solve the issue of going from having articles written by Einstein to having them written by random people, but it doesn't seem to work so well in practice. The problem is that topics whose framing is seen as relevant by some group or another (which is an absurdly large amount) drags in partisans, corporations, politicians, intelligence agencies and the rest of the dreg. And it leaves Wiki really hurting for quality on these pages.