Schubert must be somewhat popular in that his music is still reknowned years later, as is the case with many famous classical composers.
So are you saying that Schubert should be topping the charts and not the BEPs or Katy Perry?
Will today's pop acts still be popular 100 years from now? Time is the true test no doubt. It will be a different world then for sure.....
BAch, Teleman and Handel are pretty much the only original modern music makers of note to western civilization (can't speak for eastern or other non western civilizations or cultures which might have a different perspective) that have achieved or retained a high relative level of popularity hundreds of years later. I suspect only a select few acts from teh last 100 years will achieve a similar legacy 300 years from now.