Even today on HN most use chrome instead of firefox and mac instead of linux and. If you can't even convince the biggest nerds that supporting alternatives is important, what chances do you have?
How the hell is chrome significantly more secure than firefox?
No single app has access to any data thanks to hardware-assisted virtualization. Last time a VM escape in the modern Qubes implementation was discovered in 2006 by the Qubes founder: https://en.wikipedia.org/wiki/Blue_Pill_(software).