Just putting this out there for discussion, and because I can't currently think of why it wouldn't work...
Imagine you converted every pixel of a bitmap image into a vector square. Could you then resize that image (or the collection of vector square "pixels") proportionally and infinitely, essentially creating a vector-bitmap image?
What would be the limitations or hindrances of this?
If it's possible, couldn't it be implemented anywhere and everywhere (eg. like svg for websites, etc.) so we no longer have the "raster-images-get-blurry-when-enlarged" problem? Some sort of automatic conversion tool (ie. open/import a bitmap image and it's automatically "read" and converted to a vectorized-pixel image), even within Photoshop itself, that could turn any old raster image into a fully responsive vector-pixel image?
Why hasn't this happened yet?