Most likely, most people can be taught to read music and learn to play other instruments. However, it is more difficult than learning how to read or play. Many people are reluctant to practice because they do not know how. For example, it is not easy to learn to play piano without a teacher that listens at you while playing, and the teacher has to watch you play or teach you. Many people think that just because someone is good at piano at a young age, this means that they can be successful playing piano. However, this is a myth that is not based on research or data, but on their own feelings and experiences.
Many people are afraid to move away from piano because they think that the piano will “break”. This is a misconception that is often repeated (even by people who play the piano, like teachers, who do what they call break the piano). They may be afraid that if they leave they will not be able to play piano well.
Why do pianists make it a big deal to play music (and not learn to read or play other instruments)?
People who are good at piano often assume that they must play everything or be professional. This is not true. Piano players (both professional and amateur) make a living out of playing piano and other instruments to perform and to learn.
The majority are musicians, not just fans. The most famous pianist in the world, Gershon Kingsley, is a world famous world famous rock bassist who learned how to play, played piano his whole life, and is extremely good at it. This is not to say that he has not studied other instruments and can play well on a computer. Just that he spent most of his life learning how to play as a serious musician.
Many students play piano not just for enjoyment (e.g. to learn the musical style and learn how to express themselves) but also to learn the piano. The idea that they must have studied other instruments or they are not good at piano is a myth. There is no reason to think that students in any career field must study other instrument and not make the most out of their training. Just because they are in a particular career field doesn’t make that field inferior.
Do piano teachers have anything other than experience?
Yes. Piano teachers practice, teach and improve their skills in both listening and teaching. One of the most important things to learn is patience and focus. Many people need to be exposed to a long learning curve