Fortunately this model is still partially used for some careers like medicine and veterinary practices where you have a mandatory internship of at least a year before you can be admitted as a practicing GP or Vet.
That's a good way to think about it, though one still has to ask: "An apprenticeship in what?" Optimally thesis means you're given a nebulous problem within an area of interest and asked to manage a project to solve it and communicate the results. My own field, physics, is particularly loose in terms of what tools you might need to adapt and create.
