[zmb_]

I would add a word of warning here. In the multiple research groups that I've worked in, the completion rate for industrial PhD students has been way less than 50%.

The industry part (whether 20% or 50%) easily ends up being close to 100% in practice. And many industrial PhD positions only last a few years, after which you get a normal full-time position and are expected to finish the PhD on your free time. Realistically, this makes it practically impossible to conduct the kind of research that you need to get a PhD from top programs.