In my experience, the thesis doesn't properly test the skills involved in being a researcher. All it shows is that you've done some research, and that you can write and talk about it given a large amount of prep time and guidance. Without any publications, it's hard to judge if the PhD knows how to do peer review for instance.
On the other hand, after having gotten through a couple of publications, a couple of seminars and at least one peer review process, the thesis becomes almost just a formality. Since by then you've already had plenty of experience writing, dealing with criticism, and presenting your work to experts.
On the other hand, after having gotten through a couple of publications, a couple of seminars and at least one peer review process, the thesis becomes almost just a formality. Since by then you've already had plenty of experience writing, dealing with criticism, and presenting your work to experts.