There is only one flaw I can see in your argument.
It's kind of like saying Hannah Montana/Miley Cyrus is a better musician than Beethoven because she sells more albums, has a TV show, has a movie and sells tons of merch.
Popular in market A does not mean 'better' in any market... just more popular.
Oh, and here's my jab - I don't recall the TOS Trek series 'borrowing' a fist full of themes from 'Dune'. Star Wars is so loaded with them I don't know if I should start at the 'spice smuggler', the 'desert planet' or perhaps the 'sandworm' they call a sarlack or something of that nature.
Really, it all boils down to this - It doesn't matter which one is 'better' than the other.
Both are pretty awesome in their own right and I'd not want to have a scifi world without both. :laugh: