Do people have the same sort of expectations concerning accessibility with other forms of media or activities?
E.g:
Should James Joyce's Ulysses have a "translation" into more understandable English? Is this translation still Ulysses?
Should the board game Twilight Imperium have an alternate easy to understand ruleset? Is this game still Twilight Imperium?
Should tee-ball leagues exist alongside wherever baseball is played so everyone can play this ball sport? Is tee-ball still "baseball"?
Given that Reader's Digest, "family" versions of popular board games, and tee-ball (as you point out) all exist, clearly the answer is yes, people do have the same sort of expectations concerning accessibility with other forms of media or activities. Whether or not, or to what degree, those more accessible forms of a thing should be considered distinct from the original thing is a different question. I think most people would acknowledge that playing a game on "easy" is not the exact same activity as playing the same game on "hard".