This question has always come up while I'm learning new music. How many pieces do pianists learn every year? I've seen recordings of great pianists like Vladimir Ashkenazy who has recorded All Chopin Rachmaninoff solo and concerti Shostakovich P&F Op87 All Beethoven sonata and concerti All Mozart concerti all Scriabin sonata Liszt Transcendental Etudes And much much more. Then there's Jeno Jando who's got All Mozart sonata and concerti All Haydn, Beethoven, Schubert Sonata Liszt Hungarian Rhapsody, transcendental etudes, sonata, years of pilgrimage Bartok Rachmaninoff While I'm here struggling to learn these pieces, pianists like Ashkenazy among the other greats, knock these pieces out of the park. All I have is Chopin 4 Scherzi, 4 Ballades, Fantaisie Op49, 3 Etudes Scriabin 12 Etudes Op8 (close to finishing), Sonata no2 Liszt Transcendental Etudes (getting 6,7,8,11), 6 Paganini Etudes, 6 Consolations, Nocturne in Ab, Ballades, sonata Mozart Sonata K330,332 Then there's the random stuff like a few Debussy Preludes, Burgmuller op100 It's not a big accomplishment at 27 years of age. I've seen people at this age have twice this amount of pieces in their repertoire. Is there a way to accumulate a massive piano repertoire in a period of the next 10 years?
The difference between the professional pianist and the other great amateurs, IMO, is their power of assimilation. There are many anecdotal stories of the greats learning works with the barest of efforts. This is no different than the great actors who learn Shakespear quickly and easily.
Concert pianists have time to learn massive amounts of music, mainly because that is their profession. For us amateurs, that is not the case. I work a lot, sometimes up to 12 hours a day. I can therefore only learn a new piece once every two months or so. It also depends on how difficult the pieces you are trying to learn are. You could learn 5 Bach inventions a lot faster than you could 5 Chopin etudes.