I think it's like classic cars.
You could buy a shell and then spend lots and lots of money getting original parts, restoring it, getting custom made stuff to fit and eventually end up with something kinda like the original.
Then comes these kit car companies who will sell you the thing which is 99% the same as original for a small percent of what it would take to do the job yourself.
Its different but the insane expense of getting all that done yourself is a barrier of entry to a lot of people.
To get the ultimate franken would be the same now as it was before (gen dials, hands, crystals, etc.) but those who would rather get 95% there instead of 99% can do so at minimal cost. They can also take up relatively minor mods without very much at risk. Because of these cheap reps I can safety go and try to relume my dial, fiddle with my movement or reshape my crownguard without thinking (damn if i fk this up this will mean a month's rent).