There are a few alternatives, actually. There is also Element (based on Matrix), and XMPP which use encryption based on the Signal Protocol. Both are mentioned

There are a few alternatives, actually. There is also Element (based on Matrix), and XMPP which use encryption based on the Signal Protocol. Both are mentioned in the article. And yes: users are locked in, because your whole social network is expected to be on WhatsApp. 1) you need to convince others to find you on alternatives (every single person even people you just met, you have to explain what&why; also: workplace, clubs, etc. or leave them). You certainly aren't going to convince everyone 2) you will miss out on a lot: people are being invited into groups, but they can't invite you anymore to just join; people create groups on the messenger they use most often, because it is more convenient for them. In summary, if you have a active social life and grow/grew up with it you will have a lot of friction if you really want to get rid of it. That is what I would call locked in.