can aim to sound "timeless" but it's still a complete crap shoot.

Every decade and era has a different definition of what the "timeless" music sounds like, and what the completely dated "you had to be there" music sounds like. Problem is, when you're in an era, you can't really tell.

I feel that the super trendy sounding music that comes out will NEVER be seen as timeless, at least in this era, but I really can't tell you what will be. For R&B, I've always felt that live instruments help a lot of songs sound timeless, verses anything that's too synthy...although much of the Minnesota sound (Prince, Mint) was synthy as hell. But like a Beyonce "Video phone" type of song just screamed "trendy, only gonna be hot for today" while the vocal arrangement and changes on "Love on top" feel like that might be our favorite song from her in ten years.