website design – Why are toolbars at the bottom of screen for video-conferencing applications?

All of the leading video-conferencing solutions like Google Meet, Teams, Zoom, Whereby, etc… have the main toolbar at the bottom of the screen. What is the reasoning behind it?

Shouldn’t it be more logical to be on the left-side, because monitors have more space horizontally? By putting the toolbar at the bottom, isn’t it eating the less available vertical space?

Also when a panel like participants is opened it goes either on the left or on the right side, so if toolbar was on the left it could open nicely next to where the user clicked. When it is at the bottom, you have to move the mouse much more to reach it after the left panel opens.

So I am very curious to know the reasoning behind putting the toolbar (video/mic, etc…) at the bottom of the screen.