Let’s take a look at that exponential pixel grid that the resulting files consist of.
There is always a square center, consisting out of several smaller pixels, this is the most detailed area. When moving away from that center, the pixels will grow exponentially.

This follows clearly defined principles: Each new row that is surrounding the center contains the same amount of squares/pixels as the row before, making them grow automatically.
That results in a constant resolution, no matter how much the file is zoomed. This is the most effective way of dealing with this issue - only necessary information is being stored.