it would be possible to parse any program or any bit of software into its text equivalent and then generate the URL that attaches to this algorithm for that entire page reducing a thousand characters to 16.
This can’t work. Let’s use a simpler example, instead of 16 characters for the link let’s say it’s a single digit and let’s say the content of the “page” is 4 digits. One digit has 10 possible values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. 4 digits have 10,000 possible combinations. With only one digit to index into the 10,000 possible combinations, you can point to only 10 of them.
It’s the same thing for pages of text. If you have a 16 character link and the content you’re trying to index with it is more than 16 characters then you can only point to some of the possibilities in the larger set.