... are obstacles to writing having to do with the larger picture. They can come in the form of personal doubts. Thoughts like "I'm not good enough to do this" or "Scholarship is really not that valuable anyway," or "They won't promote me even if I do write this book." They can also come in the form of serious illness, or being in a position where there is not sufficient time for scholarship (4/4 teaching load).
In my case, I was stalled for a while in the late 90s and early noughts. I kept re-configuring my project. I published articles still, but could not seem to get that next book project out. Having to commute between Kansas and St. Louis was very difficult (as it still is). I was very depressed for long periods of time. Being told that "you're only good at writing books" made me not want to write a book--perversely. The way I resolved it was to embrace my ambition rather than being embarrassed by it. A therapist I had who always told me that being productive would not make me happy... With all due respect, I am much happier now that I have found a way to be more productive. Unlike other addictions, being addicted to publishing books and articles is completely healthy. Trying to be less driven was not getting me anywhere.
If a threat is existential and self-generated, as mine was, then it is susceptible to solution. In this case it is a matter of turning existential issues into pragmatic ones, in other words, cognitively redefining something that was existential and making it a practical set of obstacles that can be broken down into component parts and resolved. If the existential obstacle really is existential, then you still need a healthy dose of pragmatism, involving figuring out whether you can still do some scholarship under desperate circumstances.