Well, as usual, the truth might be found at some intermediate position. While it is certainly true that you can correct geometry such as falling lines later in Photoshop, and see little loss of quality if you start with extra resolution and the degree of adjustment is moderate, it also is true a dedicated PC lens can do the job quicker and even better, but of course at an additional cost. Creating "deep" sharpness zone by application of the Scheimpflug principle is easy with a tilt/shift lens and dare I say, awkward at best in Photoshop. On the other hand, mimicking reduced depth of field to create a "toy impression" is easy with a tilt/shift lens and even easier in Photoshop.
Thus one has to find the appropriate balance in each situation.