It’s very hard to break the inertia of community and reputation. So there are at least two video streaming apps available… jitsi which is free and zoom which is paid and has a history of security issues (I’m ignoring hangouts here largely because google ignore it, and there are probably others I haven’t heard of).
Everyone went for zoom because everyone else went for zoom. Then the security issues became well known and… people still went for zoom.
Every time we hear something bad about facebook it has 0 effect because nobody even remembers there are other places to go any more.
Chat is the same… Even free ones can’t break in… Signal, Telegram… heck, even IRC is still out there… but use is minimal because for most people they’re talking on FB Messenger (which is actually a signal implementation) or WhatsApp.
That’s not to say disruption can’t happen - we’re sat here on a discourse server which became the dominant board software after years of phpbb and vbulletin being the top dog. But it’s rare, and 99% of the people who think their software is going to be the one to cause it, are wrong.