> Source: my grandmother, who played these rules with the inventor of Scrabble back in college, before he had sold the game for mass distribution (they changed his rules to simplify them)

The inventor of Scrabble graduated college in 1924. He conceived of and developed the game in the late 30s while he was working full-time as an architect. He didn't start producing the games 'til after WW II, in 1948. He sold the rights in 1952.

Source: https://en.wikipedia.org/wiki/Alfred_Mosher_Butts

I'd love to hear more about how your Grandmother who must have been born no later than 1905 played Scrabble in college with Alfred Butts.