You don't seem to understand what made past great works great, or what it takes to make a successful work of literature today.

That part is new. Very well, let us assume, for the sake of argument, that I don't. Enlighten us.

empty slogans

Woe! "Rationalists should win" is an empty slogan now?

I have a wonderful answer for this that my margins of time are too narrow to contain right now. I'll get back to you on this in July, when I'm done with finals.

What, and miss out on Isaac Asimov's Foundation series and The Caves of Steel and I, Robot and...?

Well, Values Dissonance aside (as in "Why don't you just not shoot him?"), a lot of old stories, especially tragedies, rely on people being stupid, stubborn, impulsive, and otherwise unwise. And this can be silly.

they do often tell you a lot about the evolution of fiction as an art form.

Hence why I thought it might be easy to see where there was room for improvement using more modern techniques.

literary canons tend to be retconned from contemporary works of great resonance

Er, I don't get what you mean here...

Fix the story? For who? For what purpose? For us, the 0,1% tail of the distribution? The smarty smart pants adults?

If you are unable to successfully reach out to everyone, that's your failure as a writer.

To be fair, TTBT episodes are short and easy to watch. It's the fiction equivalent of candy, or of a casual game. Could you have a look at the DVD sales?

The value of literature isn't in its entertainment value.

Where, then, does it lie, precisely?

Chances are that if you read something in high school, it was both literature and not very entertaining.

Never happened to me. Even The Great Gatsby, which I loathe, is entertaining in that it has cool prose and witty turns of phrase, much in the same way that the operation of a very well-designed torture machine is entertaining to an engineer, without the engineer ceasing to find it loathsome in other ways.

It's a base factor that is correlated with popular success (financial success, to a creative type, is secondary, as long as they're making a decent living; the important thing is to have "lots of people watching your shit", as Trey Parker and Matt Stone put it). Increasing it is no guarantee, just like raising your child with excellent values and work ethic and a good school doesn't mean he'll get the Nobel or even do anything important with themself, but still, it's what you do if you want them to succeed as much as possible.

However, for the record, I'd argue that a show must be "good" for a purpose. There's no such thing as "good" in abstract. MLP;FIM was designed with the main purpose of attracting little girls and their parents, keeping their attention, and selling them toys. The authors made sure it was "good" for that purpose.