This is really interesting. I teach younger kids, primary 6-7 age 9-12 but I saw a gradual spread of turned of camera and lack of audio from my class over our second lockdown at the start of the year. As I was using teams, I used the text chat and got a lot more responses and considered ones using that.
Interestingly some of my class were in school, essential workers kids, there were a lot more vocal I presume because they were sitting in a room together and gained confidence from that.
I do occasionally use online responses in class and I’ll be thinking of easy ways to incorporate that in the future.