It should be easy for a writer to manage to blog regularly. And, I am a disciplined writer, at least in the sense of getting my butt in the chair and writing, nearly every day. The days I don't write, I'm editing.
Even when traveling, I write. Sometimes only in my head, but that counts as a draft too, as I recall what I wrote and do get it down, even if I find the remembered text needs work.
But blogging is something else. It's not creating a story in the sense that writing fiction is. It isn't (and shouldn't be) simply announcements about things I want to sell you. It's about sharing thoughts or experiences.
The problem is that often those thoughts and experiences are the grist for the fiction mill. Spilling them out in a blog reduces the storehouse. That's why so many writers write about writing in their blogs. It isn't that they don't want to share other things, but that they prefer to share them in another format.
Sure you can reuse experiences, but they don't taste the same the second time. Some of the flavor goes out of them. So, to blog, I look (and wait) for things that don't suit stories and sometimes it's hard to tell what does and doesn't.