One anecdote ... Serving on a university-wide committee, I found that in one field (I think zoology?) the norm is having the advisor as co-author; and when the advisor does not appear as co-author it is taken as a sign that the advisor has a low opinion of the thesis.
During my career, there are only two Ph.D. theses that were published with me as co-author.
One case (Yuri Dimitrov): After the degree was completed, the thesis had to be abridged for publication. Dr Dimitrov would come to my office once or twice a week and show me his progress (much as he had done before the degree was completed). In the end he suggested joint authorship for the paper. Subsequently, we wrote another joint paper extending the work.
Another case (Jeff Golds): This guy, upon completion of his degree, was raring to begin his career in the software industry. It was clear he would never publish the work, but I thought it deserved publication. So I wrote it up for publication, and it appeared as a joint paper.