Just anecdotally, only one of my chat groups on WA have moved over to Signal an that's because it's a group of four of us (we are long time friends who use the group to talk about our favorite sports team)
With my other far larger groups it's been a struggle to get a majority of members to care enough about this.
The reality is that most people moving to Signal/Telegram will end up having to keep WhatsApp anyway.
It's the same for me, lots of people came over, but not everyone (especially large groups). WA is particularly entrenched in the Netherlands, so it's difficult to get to the point where you can completely remove the app.
But I still consider what's happened so far a major win. Breaking the monopoly WA has on text messaging is important.
With my other far larger groups it's been a struggle to get a majority of members to care enough about this.
The reality is that most people moving to Signal/Telegram will end up having to keep WhatsApp anyway.