I wouldn't have a problem with a handful of well assembled compilations with little or no repeats among them. The good thing about them is that with a catalogue as large as Elvis' (not speaking of the current 50 but the original titles), as a new fan you really wouldn't know where to start, or what this or that album is all about. The compilations make those initial purchases easier. Also, it's pretty impressive if you see that Elvis recorded music in such quantity and in such a diverse range of styles that you can legitimately compile however many different themed compilations.
What's no good is all the Artist of The Century-like, best of / greatest hits compilations along with numerous gospel, love songs, etc., etc. collections...and that they take up all the room on the store shelves when plenty of essential original titles aren't available.