Life is really too short to devote one extra minute of your time to a company as well as a profession that is not everything you had hoped for..
Good letter, but somewhat unfortunate that you might get all the way to the end of a career before this dawning realization sets in. Surely it is better to face harsh realities sooner and vote with your feet, rather than let yourself get ground down to this level of motivation and lack of satisfaction. Only the big G knows if you are going to make it through to draw that pension, you might as well be enjoying yourself on the way there...