There’s no real need for a plug to be able to sense what voltage it’s plugged into. That would be handled device side, not plug side. And for devices for which handling both 110 and 220 makes sense, well those pretty much universally already have a switch mode power supply that does so automatically, or at least a dip switch with which a user can manually select their grid voltage (check your phone or laptop charger, I can virtually guarantee it already supports both).
And the issue with devices that don’t already do this, is generally that they are basic resistive or inductive loads (anything along the lines of heaters or motors), with little to nothing in the way of digital control electronics, which need to be designed for a specific input voltage in order to achieve a specific power output. Making these devices both 110V and 220V compatible would require either giving every single one of them a voltage transformer, or to include a 110V motor/heating coil, and a 220V one, that can be switched between. Both of which would massively increase the price of these devices.
There’s no real need for a plug to be able to sense what voltage it’s plugged into. That would be handled device side, not plug side. And for devices for which handling both 110 and 220 makes sense, well those pretty much universally already have a switch mode power supply that does so automatically, or at least a dip switch with which a user can manually select their grid voltage (check your phone or laptop charger, I can virtually guarantee it already supports both).
And the issue with devices that don’t already do this, is generally that they are basic resistive or inductive loads (anything along the lines of heaters or motors), with little to nothing in the way of digital control electronics, which need to be designed for a specific input voltage in order to achieve a specific power output. Making these devices both 110V and 220V compatible would require either giving every single one of them a voltage transformer, or to include a 110V motor/heating coil, and a 220V one, that can be switched between. Both of which would massively increase the price of these devices.