I mean that's the case for any genre. Time filters out the bad stuff from the past, the good survives to reach new generations. Now we get to do the filtering for future generations.

Meh. Depends on band/genre. There's Green Day is Metallica's kill em all radio for some reason. I love both bands, but they're not really related.

There's static-x and Korn in megadeth's radio.

If you go to cannibal corpse's radio, out of 2.5 hrs of music/40-50ish songs, you'll see 6 songs by cattle decapitation, 4 of which from the same album. For a genre with hundreds of bands, that's piss poor variety. And ofc bunch of other bands in there there aren't death metal such as slayer or venom.

Sorry, end of rant.