certainly could, and did. What enabled digitization and reproduction of digital audio were the works of Nyquist and Shannon, work that showed how it would work.

certainly could, and did. What enabled digitization and reproduction of digital audio were the works of Nyquist and Shannon, work that showed how it would work. FFT is an elaboration useful for filtering and spectrum contouring, and for compression. But "Digital Audio" is not a synonym for "Compressed Digital Audio". And digitization had to be a precursor for applying an FFT filter to the digitized result. FFT is _not_ used to implement the digitization itself, and is useless on its own with the digitzed sample stream to work on.