First, the security solution already exists. I don't think I've ever seen a gas oven that didn't turn off the gas if it wasn't alight, and it would now be illegal to sell one.
Second, money would be better spent improving appliances' basic functions, but most people won't pay the extra. With most irons, the soleplate is unevenly heated and the temperature swing as the thermostat cuts in and out is too wide. Human minds are flexible enough to cope, but automation would probably play safe so the temperature would be lower and clothes wouldn't be well ironed. People would switch to manual and wonder why they'd paid for connectivity.
Anyway this is not the future I was expecting. Having a robot to set the controls of the iron so I can do the ironing seems a sadly limited ambition.