I believe that to find some backwards echo from the future one might look to the prolific artists rather than the temporally localized fame that we attribute to good bands. So I would look to singer/songwriters like John Darnielle or others with a huge catalog to survive the test of time. Not that I expect others to find his actual musicality timeless but rather the mass of the catalog helps against the worms going in and the worms going out.
That's why I consider my holy trinity of 1950-beyond to be Tom Waits, Nick Cave, and Lou Reed. They have massive discographies, they innovated while also borrowing from the past, and they kept getting better. Definitely cosign John Darnielle, too. I don't think I respect any songwriter more.
John Darnielle, Stuart Murdoch, Jeff Tweedy, Elliot Smith, and Dylan Baldi probably round out my five favorite songwriters (not necessarily musicians or bands) of the past twenty years. Going beyond that, Tom Waits and Lou Reed are hard to top. I have to throw Van Morrison and Brian Wilson into that mix though.