Whoah! Don't throw the baby out with the bathwater here. I'm all for playing new or rarely performed pieces, but there is a lot of good stuff in the "standard repertoire" too. Whay make it either/or; there's room to do both.And at times when piano composition was in its "golden age", all the best played a mixture of old and new.
That proves it....
There was a post years ago that discussed the idea that popular classical repertoire is defined by established pianists. As in there will probably always be a set of accepted standard repertoire, but that what fills that list can be molded by well known performing pianists who choose to play unknown works on a big enough stage.
Moulded, perhaps, but not defined. Ultimately, it is the audience that determines what is and isn't "standard" in the repertoire. Bums on seats. You can't be a "well known" pianist if you only play to empty halls, and you can't influence an audience if there isn't one there to start with.
If I offer a contradictory opinion will you stop saying we are the same person?
If you're really not J Menz, the truth will come out eventually. Let life run its course.
Thats why it has to be established pianists, moulded probably is a better word. I suspect even the most respected pianists would lose their audience if they played exclusively unknown works.