Yup, with most aftermarket sets the life is limited by the rear sprocket rather than the chain- especially if you go with an alloy one.
On the subject of which, all alloy sprockets that aren't Renthals seem to be rubbish, by all accounts. The Renthal one I have fitted looks to last about 2/3 as long as an OEM one, though to be fair it's getting a much harder time than the original one did. But it looks so nice
Also, aluminium sprockets are extremely vulnerable to worn or stuff chains, they tear up in no time if you don't look after the chain. There's a theme emerging here...
Personally, I do most of the change myself- I replace the chain and sprockets and fit the new chain with a clip link, then ride to my dealers to have them fit the rive link. Costs me a fiver.