Why I haven't written a novel or produced anything mildly important despite the time my job affords me

I grew up in a family where business is our life and our life the business. My dad is a doctor in private practice. My grandparents owned a country & western bar. My uncle took over the bar and opened an ice cream shop. Another uncle owns a fish market. Another a painting business. 3/4 of my neighbors growing up own their own business. So it's really no surprise that I derive a great deal of satisfaction from working hard and being in control of my work.Fast forward through the jobs I have held since high school and it's safe to say: Challenging? Sure. Rewarding? No. This is a frequent topic for me.

"Writing novels is hard, and requires vast, unbroken slabs of time. Four quiet hours is a resource that I can put to good use. Two slabs of time, each two hours long, might add up to the same four hours, but are not nearly as productive as an unbroken four. If I know that I am going to be interrupted, I can't concentrate, and if I suspect that I might be interrupted, I can't do anything at all. Likewise, several consecutive days with four-hour time-slabs in them give me a stretch of time in which I can write a decent book chapter, but the same number of hours spread out across a few weeks, with interruptions in between them, are nearly useless." ~Neal Stephenson

I came across that quote after digging around 43Folders which led me to: Making Time To Make. I found Stephenson's whole essay. I will state right now that I'm utterly jealous that I do not have something to make even though I have more free time than most people can handle. I certainly can't handle it. It is uncomfortable and crazy-making to have the time I do without having a project to focus on. Working on that.The bolded sentence is exactly how I feel. I am, first and foremost, mentally committed to my job, so no matter how much time it affords me, I am distracted, concerned and basically unable to focus long enough to produce anything of value. (I know I sound like a whiner, but really, the first step is to admit you have a problem, right?)Add that to the fact that I don't know what I want to do, that I measure my worthiness in the world against how "productive" I am, and we can see the escalating issues. I feel unproductive, alone and bored almost every day. It's a challenging place to be. And it also feels so so so dumb. I have a job that affords me paid time to do whatever I want and I can't bring myself to do much of anything! It's a direct result of what Stephenson mentions above. The thing is, he figured out what mattered most to him and chose to focus his energy accordingly. I'm off-course and lost until I do the same.