I don't think that's true at all. I think that's just modern fiction giving that impression. Especially in the case of butchers.
Actually, it's somewhere between the two.
The living quarters were always in separate areas (such as a building sharing a wall) or upstairs, not on the same floor as your business. (Miss Piggy, when asked under what sign she was born, replied "A butcher shop.... It was a close call.")
In the case of butchers, the persons dealing with meats weren't slaughtering the animals - they'd typically do that at farms, corrals, or stables (Horse! It's what's available for dinner), cut it down to sections (if needed), then taken to the butcher's for final prep (even the blood was collected for various uses, either in food or construction - the Romans actually used animal blood in some of their concrete mixes for its binding properties!). Then, if not sold fresh, was taken to distinctive separate buildings for curing/smoking and/or storage (such as cellar filled with river ice).
Butchers were probably some of the first modern professions to industrialize, as the wars ramped up around the time of the Renaissance & Reformation - because of the needs of feeding armies that had grown too large to feed themselves via scrounging the countryside (especially after they killed or drove off the locals, or driving out the invaders that did the same and scrounged everything already). Before then, most stuff was done on the farm, and the only professionals of that type were probably part of the local nobility's tax collection force (who had to convert the tax paid "on the hoof" to food for the lord).
