I believe that liking what you do for a good pay may be a very great blessing but it is certainly not a prerequisite for a productive career.
I have been on several sides of the fence: employee, freelancer and employer. I belong to the much maligned upper part of the 1% if that happens to be any indicator of a successful career.
The whole issue really boils down to your attitude. If you subscribe to the idea that you work in order to be able to live in comfort, you are nailing it in the head. You are harboring realistic expectations, and are not suffering from delusions in which someone pays you for something that you really want or need or would like to enjoy but for what they want, need and want to enjoy. Truth is so rewarding because it sets you free.
Now, quite a few people insist that they can only do what they like to do, and fear that otherwise they would be failing pretty much every step of the way. They are really voiding their lives of its content by reducing it to the world of work which is usually controlled by someone else. Once either specific people or market forces decide that your work happens to be superfluous or in very low demand, you are looking into the 'game over' syndrome unless you have a great talent of reinventing your love and yourself at a possibly very short notice. I do not envy these people at all