Also, keep in mind anything that could conceivably be called a "file" is fundamentally an arrangement of atoms in a measurable state which can be resolved into an ordered sequence bits. Whether that's a capacitor holding or not holding a charge, of a bit of spinning iron oxide with a measurable magnetic orientation - any actual "bit" is made up of many atoms, and any ordered collection of bits requires many more atoms to hold them in their ordered arrangement (and many more atoms to provide the capability of reading this bits).

A terabyte is 2^40 or ~10^12 bits. A hard drive weighs, what, a few hundred grams? Guessing an average molecular weight of ~50, that represents something like 10^24 atoms - suggesting a "bit density" of around 10^12 atoms are required to store each bit.

Even if you turned every single atom in the universe into hard drives to store your files, and stored every possible arrangement of bits you had space for in all that storage, your chances of a 256 bit hash collision is still way smaller than your chance of winning the lottery.

Big numbers are often confusing. 2^256 is a very bit number. Although abstract mathematics makes if easy to say "yeah, but 2^512 is bigger", it's only bigger in an abstract sense, and not useable in any arguement along the lines of "well, if I had 2^512 physical objects"...