Wire is open source, according to the article, but has long as it isn't an open standard and decentralized, it's useless.

Being able to run your own free-software server on the network makes it much, much more robust and resilient against government meddling or commercial fads of the day by the owners.
Note that I said "being able to", as you can still let a trusted third party to do it for you, just like e-mail, jabber.