There are no cheap windows 95 computers where everything works on the market. Android 4.4 does do everything people need (like running whatsapp), and the devices are out there to buy.
Security vulnerabilities? Nobody was ever affected by those (at least in the social circles of the people buying the devices), so why should they care?
Tons of sites full of "amateur porn" think you shouldn't worry either. Who cares if all of your pictures are freely available to anyone on the planet, right?
Security vulnerabilities? Nobody was ever affected by those (at least in the social circles of the people buying the devices), so why should they care?