Mostly just plain old Open Source stuff: mediawiki (same as wikipedia), an IRC server, an email server... I find it weird that people tolerate depending on any

Mostly just plain old Open Source stuff: mediawiki (same as wikipedia), an IRC server, an email server... I find it weird that people tolerate depending on anything else. You are at the mercy of some other company. They can cut features (for example, confluence killing wiki markup compatibility to lock users in), they can jack up the price, they can totally discontinue the product, they can switch licensing, they can require an always-on backdoor for "upgrades" or "licensing", and so on. Why would you tolerate this risk to your business?