I like old music because old music really is better. Most of the (non-"alt") music that I listen to was written and recorded before I was born.
It's not that old music is "killing" new music. It's that new music has been slowly killing itself since the 2000s. Even the Backstreet Boys and Three 6 Mafia seem fresh and interesting compared to the stuff I've been hearing on the radio over the last decade.
Even probably the best (IMO) pop artist of the current era, Stromae, writes songs that are mostly the same hooks and background elements repeated over and over for 4 minutes, with no change in dynamics or structure.
I'm honestly pretty sick of all the 60s-80s stuff I've been listening to, but what else is there?
Don't get me wrong: there was plenty of stupid garbage in those decades too. But the great stuff truly is great beyond most of what we get today, at least when it comes to stuff that's considered "mainstream".
But if the record industry wants to destroy itself, who am I to stop them? Keep listening to (and paying for!!) alt stuff, that's where the personality and creativity is.