Which begs the question, " How many DIYers have a decent 1/2in router?". Whereas quite a few people seem to have a power planer - albeit a domestic model which can only take 2mm per pass as opposed to 4mm per pass of an industrial one.
Fair point but you can get a decent for DIY 1/2" router for well under a £100. Both my brother and myself as DIY'ers have decent for DIY 1/2" routers.
Another point about router cutters that you didn't make - it is normally regarded as unsafe practice to take a cut with a router of more than 1/2 the diameter of the router cutter - so with a 1/2in diameter bit you shouldn't be taking more than 1/4in per pass because of the increased risk of experiencing a climb cut
I was under the impression that a climb cut was down to the direction of feed, nothing to do with the depth of cut. Limiting the depth of cut is to do with stressing the bearings on the router, on small diameter cutters the risk of snapping, and it does depend on the material you are going through. So oak requires shallower passes than pine, though if you are not doing a "cut" a full depth pass is definitely acceptable.
So the twaddle (to use your own verbiage) that you are trying to peddle is that the vast majority of trade joiners, who don't use routers for this sort of task, are complete numpties who don't know what they are doing?
A trade joiner is interested in making a good enough job in the quickest time. They are almost never interested in making the best possible job regardless. The OP asked what to use to get and I quote "the best finish", which I maintain will be achieved using a router.
Also for a DIY'er using a router has a far lower skill set requirement than planers, or saws and batterns, with far lower probability of a cock up being made.
I do almost all my own DIY because the job I do is almost invariably "better" than a professional. I might take longer but the quality of the finish is better than any trades person I have ever personally seen because I can spend the time without cost becoming an issue.
As for doors, over the years I have used all the methods described in this thread, but would reach for the router every time now.