It's not really the technology that's at fault, TBH. IMO, digital TV has brought great benefits over the analogue system which really was behind the times (I don't hold the same view when it comes to DAB radio, but that's another matter..)
The problem is the user interfaces on most consumer equipment. They present to the user a view of the inner workings of their TV instead of simply allowing them to do what they want - watch channels.
All that happens during these "retunes" is that the channels get shuffled around the various multiplexes. On the whole, the same channels are still there, with the same IDs, but perhaps in different places, so the TV developers could, if they could be bothered, hide the whole operation from the user so they never knew it happened.
Technology is very good at hiding complex workings from inexperienced users (think about your engine management ECU!), when the developers can be bothered to implement it sensibly.
As it is, consumer gear is all engineered down to the cheapest possible price, and usability is one of the things that suffers.
I am constantly helping out Mr. KW's grandmother who has a TV with a DVB tuner built-in, an analogue VCR and a sky box. Not an unreasonably complex setup to have in this day and age, you would have thought, but the number of button presses to go from the DTV tuner to the analogue output from the VCR and back is simply impossible to manage for an octogenarian, and quite a smart one at that.

Kevin