The DT I suspect is only really doing as well as it is because its the only Hilton in town. That area of the CBD has been in dire need of a refurb for at least 25 years or more. Its grubby, quite decrepit, and full of $1 style shops. Luckily for the DT, its only a relatively short walk to Southbank.
As for King st.... well it _used_ to be a really vibrant night club area 30 years ago when I lived in MEL. Those clubs are long gone now, at least 20 years and more, and, tbh, they were a thing of their time, wouldn't suit the current fashion. Once they closed though, the whole area became more than just a bit dodgy. I haven't been a resident for too long now, don't really know what its like nowadays, but I suspect, like a lot of the south end of town, it could use a bit of spit-n-polish.