At all of the nearby hardware stores, there is a wide arrangement of pozidrive screwdrivers. If I recall correctly all of my "cross" bits for the powertool is pozidrive as well. It may not be widely available in the US, but it certainly is here in Denmark.

Pozidrive screwdrivers and bits are readily available in the US but have low cultural awareness; particularly, the indicator that heads require them and not Phillips is not recognized.

Exactly so, 99% of people have never heard of posidriv and don't have the bits, or don't know they have the bits. I couldn't find anywhere in instructions or the website where Ikea mentions that you should use them, but sure enough every screw used posidriv.