Why don't wikipedia pages have like and share buttons?

One answer is because "like" and "share" buttons are intended to increase readers, and more readers are (generally) wanted because that increases revenues (advertising, sale of goods and services, whatever). Wikipedia doesn't care about advertising, and doesn't sell anything. It wants readers who are looking for information. Another answer: Because social networking options would increase vandalism. Anyone can edit Wikipedia; very few articles are protected against non-registered editing. With sharing and likes, one obvious scenario is: Person A edits an article about a high school, adding something like "Principal [X] is a [insert string of offensive nouns here]." Then he/she shares the page, and all his/her friends titter about how Person A was able to punk Wikipedia, at least until the vandalism is reverted. Or, once Person A finds out that obvious vandalism is reverted quickly, he/she starts being more subtle about damaging articles, sharing his/her amusing tweaks with friends.

I really want a wikipedia share button. I read so much articles that I would like to share. Today it was the article on Michel Lotito who has aten 18 bicycles, 15 shopping carts, 7 televisions, 6 chandeliers, 2 beds, 1 pair of skis, 1 airplane, 1 coffin, and 400m of steel chain.