Making tasteful music is the ultimate in a musician's expression, not by being a good pianist by playing etudes.
What is most interesting is that for a vast majority of pianists is that they never get beyond the pianistic problems and always confuse music making as piano playing. They concern themselves with having the fastest fingers or playing certain pieces as fast as possible to the detriment of these very musical pieces that it no longer has the meaning that was intended. This is part of the development as an instrumentalist but it is a pervasive phenomenon that few ever conquer including many well-known pianists that so many admire.
When pianistic problems are not an issue, they then turn to the musical issues and concern themselves with their ideas of music. But this is rare. Instead, when adequate control is reached for them to make music, this insufficient control leads to more and more piano playing because it is not the most perfect of control. And when this situation is elaborated by the thousands, you get a a carnaval of pianists parading their abilities to the ignorant masses amazed at what their fingers can do.
Your teacher's statement is only partially true. True in the sense that from Chopin's studies and onward, they were the most radical amongst commonly accepted piano technique. Virtually no one could play Chopin's studies because they had a different conception of technique. So clearly, in order to play these studies with great ease and expression, you already have the technique.
It's false when you consider that many who learn these studies actually play them in a manner that was not intended by the composer; id est, once they stop practicing them they lose their ability, or they do not make music... They play them incorrectly and abuse the music and their fingers.
The second statement about a limited future is very subjective. I do not agree with it taken as is but if it was said with the assumption that technique and music making are two sides of the same coin, then he is right. But he could have said the same thing about Mozart's sonatas or Liszt's music or Debussy's. I don't think I would ever want to play Chopin's studies because I don't find them musically worth while and would rather persue more interesting things. This is probably where you form your own opinions as to your musical future.
Piano playing and music making cannot be separated. Both must shine through with ease and effortlessness - this is the test I use for myself, other musicians (not just pianists) and my students. If it is easy and effortless to create music with even the most difficult of piano music, then you have entered the most basic of mastery.