Microsoft can fall behind, anyone who isn't computer illiterate or forced to use their crap at an office would use something different.
OK, even if you want to say screw IE users they two image types serve entirely different purposes. The point of .gif images is to take up as little memory as possible while still being animated. The point of .png files is to have higher resolution images with transparency, which obviously take up far more memory. So, if you're also wiling to say "Screw how long it takes pages to load." you can convert images to APNG file type. The reality is there's no practical purpose for anyone other than graphic designers to convert images from .gif to .png image type and a good graphic designer would never use low resolution .gif image frames to create an animated png file. There's no point in using a 300DPI file type if you're only using 72DPI files. In fact it makes the images look worse.
This is one of these "improvements" that isn't really an improvement unless you're creating animated png files from scratch using 300+ DPI images as frames.