It can change rapidly in small communities, e.g. you getting everyone in your department together, deciding on $goodAlternative and using that whenever possible (in addition to Zoom, because you'll still have to communicate with the outside world). But at large?
This doesn't square with any experience I've ever had trying to get $alternative_technology adopted because of $principle in favor of $default_thing, and from what I've gleaned talking to others, and reading the experiences of others online, the problem isn't me.
Maybe post Cambridge Analytica the world has changed -- I at least don't get looked at like I have three heads when I tell people I'm not on Facebook anymore -- but if folks are still responding to complaints about privacy issues like this with what amounts to "meh, don't have the energy" then I'm skeptical. If zoom becomes "the standard," I don't think the inertia will be much easier to overcome.
As soon as something goes wrong with your solution - everyone goes, why aren't we using zoom. Literally totally non-techies - that will be their first bit of feedback (I tried to go with google hangouts).
Your second point I disagree with; I think if people raise objections, encourage people to switch, and volunteer to shepherd others through the technical details -- then people will be agreeable, and we'll see a shift which will gradually become pervasive.