I got a PhD with a thesis in wireless networks and now I work in the field of high-end image processing.
A PhD (and a Master too) should give you not only specific competences but a "forma mentis" to reason and solve problem: it should not give you tools but it should teach you the way to build your own tools.
BTW... R.A. Heinlein said: "specialization is for insects";-)
I got a PhD with a thesis in wireless networks and now I work in the field of high-end image processing. A PhD (and a Master too) should give you not only specific competences but a "forma mentis" to reason and solve problem: it should not give you tools but it should teach you the way to build your own tools. BTW... R.A. Heinlein said: "specialization is for insects" ;-)