There is an unspoken assumption here from the word "literally": pieces of classical music are written in stone and are not allowed to be transcribed to fit the player's hand.
That assumption is about as coherent as anything you'd read in a Qanon Facebook group because:
1. Transcriptions from dead composers like Busoni are allowed in competitions. So if you're dead and gone, your transcription is a "work". If you're alive and playing in a competition it's not allowed, unless the student is making emendations to an already transcribed piece. So Liszt-Busoni-student transcription, perhaps ok. Beethoven-student transcription, definitely not ok.
2. The above exception is probably rationalized on the basis that these transcriptions generally add another dimension to the music. But composers like Schumann were constantly voicing chords in their own music to comfortably fit their own hands, often at the expense of more complex or compelling voicing. Yet these composers' pieces are to be played exactly as written in the competitions.
3. Hell, Beethoven was known as a goddamned master improviser. Just throwing that in there...
4. At least for tonal music, the tones of most chords can be found within a single octave. Additionally, there's a perceptual phenomenon where one can leave out a doubled note in a widely spaced chord and the listener will perceive it nonetheless.
5. It turns out that human creatures are little analytical machines that can interpret the function of chords, voicings, phrases, etc. Outside of some very famous voicings of some very famous pieces, these humans can often leverage their ingenuity to find perfectly valid, functionally equivalent voicings that both fit their own hands and the character of the music.
The piano competition world essentially says to its students to learn all these things as part of a well-rounded musical education. But then it forces them to ignore them and adhere to a set of arbitrary strictures shared by most competitions. That might make sense if the strictures were necessary to judge all the performances on a more or less objective or at least normalized basis. But competitions rely on the taste, deliberation, and fairness of judges who generally hear different pieces from each student. So you get a vicious cycle of students who are rarely forced to think critically about how to transcribe pieces for competitions, and some them later become judges who lack those same skills and thus default to perpetuating the same unquestioned strictures of competitions.
Anyway, if you changed that stale culture, there wouldn't be any need to change the size of the pianos because adapting the music to one's hand would be common practice. And if one thinks of how resistant the current culture would be to changing any of those strictures to help students exercise such an important skill, what makes one think they'd be any more open to changing something as fundamental as the size of the piano keys?