As the season goes on, you can see a clear decline in the mental health of many of the contestants. Many drop out just out of sheer boredom or loneliness, even though they have decent shelter and can find food. The winners usually last about 2-3 months alone.
The contestants (especially those who make it to later stages) are highly-skilled survivalists.
and talking to a camera and pointing a camera to myself most of the day without even a mirror or comb nearby would make me double anxious.
For instance consider the different things you need to consider whilst holding a simple conversation. It's not the same as talking to a wall. It's a game with constraints and a game that our DNA would rather have us do in order to better our chances of survival through cooperation with other members.
There was always a lot to do if I wanted to do it, and I could spend hours at a time doing stuff like making dirt-roads, practicing my dry-stone masonry, coding and whatnot on the computer.
I think if you're alone and have some purpose (i.e. building your ranch, spending time to study or learn new skills) you'd probably be fine.