If you read the Canterbury Tales, read one half way through and ask yourself how it will end. You'll be right. Plot twists hadn't been invented yet. Those now-cliche plots were new back then.
Perhaps, but I think that is beside the point. I read the tales for the voices of the characters, and for the poetry. It’s like Shakespeare, where the plot or story is usually a bit boring, more of a pretext to the poetry, and not really the purpose.
Not Shakespeare. Shakespeare's plays are successful commercial theater. They were performed in his day, profitably. They have been widely performed for centuries since, in various adaptations, usually profitably. And usually, minus the poetry.
You are right of course. The plays are plays. And ”commercial” minus the poetry ;) and yet, the poetry is there, for the non-commercial reader. (I hear they exist)