Being a professional musician means living a life of gigging, or working as a freelancer in your own business. This is the model for the majority of working Pianists and Accompanists. There are some jobs in churches, schools, universities, and cultural organizations, but these are usually part time. Having a good network and the right skills is the key to being busy as a Pianist and earning a passable living from music.
Many Accompanists work in other areas of music as well. Within classical music, including jazz, many Pianists teach, whether privately or at a school. In addition to performing as a solo artist, they work in bands, concert halls, night clubs, at events, and might also work as an arranger, songwriter, or as part of an orchestra.
There are many music industry jobs a Collaborative Pianist can fill, and it will be up to each musician to create their own career by putting them all together.