Mostly because this was a pretty huge redo of this house. When demo was done all that was left was the kitchen, one bathroom and four external walls. Just a shell. It required a new HVAC system, the formally unusable space between the ceiling and the roof was transformed into an office, one bedroom, bath and large day room, downstairs the former living room and master bedroom had cathedral ceilings that had to be made into regular ceilings and they completely redid the master bath and moved the laundry area. They even had to move the circuit breakers to a different location and new fire codes meant sheet rock in the attached garage. The support system had to be reinforced by adding a gigantic center beam to support the weight of the additional stuff on the second floor connecting up to the roof and a stair case was needed for access to the second floor which also involved changing the dimensions of the two downstairs bedrooms. So, it's to late now to make this long story short, but, they basically had to completely rebuild, re-insulate, rewire, have massive new plumbing, including in-slab waste piping.
All that stuff had to pass individual inspection followed up by a last, probably the worst, inspection to see if all the problems were caught and corrected by the previous inspections. My guess is that any future changes will be buying a new house and burning that one to the ground. They originally were supposed to be done and moved in by late August. The new target was before Christmas, that will be missed by about two or three weeks, but, there is a light at the end of the tunnel. It has been difficult keeping morale up especially with their 16 year old daughter. She has been a very unhappy, forced into, camper. Can't say I blame her considering my absolute hatred of camping.