IN CAMERA! It's all about getting it as best as can be in camera. Post………go ahead and rely on post, if you like that sort of thing.
When shooting something like architecture I don't think getting it right in camera is an absolute requirement (fewer shots, while heavily pp'ing thousands of shots of an event is a pita). You can also use focus stacking to get a large dof while keeping the lens at the sharpest aperture, you're most likely on tripod anyway.
You cannot achieve the same effect that a TS lens can do for you in PP. Depending on the amount of shift there are cases where you can get somewhat close, but a TS lens is the only real solution.
+1 - though recent software like the new dxo viewpoint gives much better results than bare lr and fixes horizontal/vertical lines, but it cannot reproduce the main advantage of a ts-lens: If doing it in software you're massively loosing resolution if correcting more than just a bit - and you need to shoot with much more space to avoid clipped parts (see sample processed from low-res source).
But in my recent, limited experience when shooting for smaller output resolutions and correcting for some angles
software is just fine, even a t/s lens doesn't move your camera so the point of view is often feels a bit unnatural to me.