As I listened to a quite fine community orchestra play the very demanding slow movement of Dvorak's rarely-played Sixth Symphony I was struck by how different the motivation must be to play an orchestral instrument than to play the piano.
One of the main differences is the loneliness of the pianist contrasted with the constant emphasis on ensemble skills for the other musicians. I have seen it happen over and over again that the pianist is expected to master ensemble skills the same way the other instrumentalists are, even though burdened with at least four times as many notes. In other words, pianists are usually thrown into the pot too soon and without the proper support to make the experience meaningful.
I recall vividly my first experiences playing chamber music: The score was set in front of me and I felt overwhelmed. It was like plunging into the Atlantic and being unable to come up for air until running aground at Southampton --and I don't mean Southampton N.Y.