All I meant with the Madame Bovary example was that just about anything can be used for escapism. In the absence of escapist media a person can simply daydream and achieve the same effect.True, but we can also deduce more from this than meets the eye; Madame Bovary is a fictional character, whose immersion in romantic literatures reflects a marginalization imposed on her by a patriarchal society. Escapism here connotes not a willful or apathetic brand of escapism, but a socially constituted escapism; an escapism reinforced by a phallocentric hierarchy.
Since I really can't say for certain, I'll have to be more specific and concede a certain point that you've already made; certain SF may be escapist, since I can't claim that all of it is good, nor can I claim to have read all of it. However, SF in general (what SF should be and should do) is not escapist.
I think I get what you're saying. In a Platonic sense, there may be escapist science fiction but Science Fiction is not escapist. I can agree with that.
As far as the structure and archetypes of literature go, heroes are never "unsung." That's an ideological perspective that we've all been exposed to; but it doesn't apply to literature, especially to literature as archetypal and structural as The Lord of the Rings. The hero, as it is defined, fills a specific functional role, and Frodo fills this function. We might like Sam, and so we idealize him and call him a hero; but structurally, he isn't the hero.
Fair enough. Let's say, then, that Sam is the most virtuous and sympathetic character, the one that the reader comes away admiring.