It doesn't matter.
If your index key is only N bits long, you cannot index more than 2^N files. No matter how much more you post, this will continue to be true.
Pi is an irrational number, which means there is no fixed sequence of recurring digits which continues indefinitely.
It does not mean that every sequence of Y digits is guaranteed to be unique.
In fact, even a few moments of thought will tell you that there must be repeating sequences, otherwise Pi would be representable by a finite string of digits, which it isn't.
So there is a possible way to end up with the same index key from two different files, and that is how you end up with only 2^N possible answers.
I appreciate you taking the time to explain matters, but I haven't your background, and I'm not sure what you mean by 2^N, so I can't actually formulate any response to your critique that will make sense to you.
Every unique file is, itself, made up of repeating strings of data, but what makes the data unique from other files is the arrangment of the data, how the 0s and 1s are arranged. Thats true for almost everything. Some popular music differs from other songs only by a few notes and the main singer, but we view almost all of it as unique, the small differences do a lot, even if its almost the same.
What I've created is a way for every bit (0 or 1) to affect the path taken to reach the index in Pi. Therefore, its impossible for any index in Pi to hold more than any one outcome.
Take 0000001 and 0001000 and 100000 for example. The index for each is, respectively:
BYTE EXAMPLE: 0000001: 0001000: 100000:
Pi Index: (57) (85) (103)
And that's just with one byte of data. The larger the file size, the more unique it becomes. You could have billions of 1 megabyte files, and if even one bit in their internal structure was different, the outcome would be different. This is truly the butterfly effect at work.