The Empire probably had 100s of Star Destroyers so why would it not make sense that some parts of it survived? The Rebels just cut the head off. That wasn't the entire Imperial fleet at Endor.
Multiply that "100's" by a few thousand.....
I don't get the hate for the Empire not only surviving but being very tenacious about sticking around and still being the big problem all these years later-think about it we're talking about a galaxy here and to control that? you'd need a humongous military to even
think of trying that,to actually do it?
Let's just say I'm very pleased with the new film and the "new" Empire and I wouldn't be at all surprised if the new trio of films ends with a stalemate against the Imperials and they being a very fixed part of the new Republic very far into the future,they aren't based on a single planet so the "economy" collapsing isn't a problem,as I said I would bet there are at least a handful of worlds who support them and would help them.
Never mind that they may be the only law in some areas,perhaps better then the one present in the old republic which if you remember was rather corrupt,I suspect a few years of bloody chaos between the warring Empire and the Rebels,then a cold war of sorts when the Empire reasserts itself-and frankly that could be a gold mine of films set between ROTJ and TFA
I like the Empire no use hiding that,but looking at the size of it? and the way it could play out? I really,really doubt they just ended with Vader and Palpy's death,in fact with them gone the whole thing may have gotten STRONGER then some of you who wish them gone may have counted on.
I hope they do like I'm thinking and make the Empire a permanent part of the SW story.