Why don't I write more?
1. Low self esteem. Don't feel I have anything worth saying. Nothing deep, nothing profound. I don't know how to bring about world peace, or stave off global climate catastrophe, or make space exploration vastly more cost effective, or extend human life.
2. Memory. Hard to write with my memory.
3. Ignorance. Can't do anything like roll off descriptions of countries based on my reading, or churn out paragraphs of comparisons between the modern American empire and the Roman Empire. because I've never studied them much. I read some books on politics long ago, but a few books that you've forgotten is a far cry from being knowledgeable.
4. The Twitter Habit. I got used to trying to say stuff in under 140 characters, hoping for a reply, a retweet, a fave, now called a like. This might be a more important reason than one would think. One is only a tab away from your blog, so why would being on twitter.com stop you from writing? Well, one is reading when on their timeline on Twitter.com, and what one is reading is not long form articles or stories like one can produce in a blog post, one is reading aphorisms, original or quoted, headlines (aka link text) either copied or pasted verbatim
[Hours pass doing other stuff]
Well, it's time to post this or forget about it, and I'm trying to generate some content, so I'm posting it.