I hesitate to even say that. Sometimes people run into something that they're just not familiar with and the customer wants everything to be like original when the job is finished.
Hack a hole in sheetrock, who cares? The stuff is 15 bucks a sheet and super-easy to cut, but plaster is different. To start with, if you're not holding the saw right and the blade hangs on a piece of lathe, a small hole to repair can turn into one running several feet to the side.
Moulding was much more elaborate and made of better materials back then. All natural materials were better back then. A lot of older trim, you just can't get anymore and have to make it from scratch.
Usually the price of a job getting blown out of proportion isn't due to one thing, but a series of unforeseen things, each costing more and adding up.
You wouldn't believe some of the stuff I've run into over the years, though. There was one that the owner had some plumbing work done on an older building and the pipes were run through the ceiling. He called me after the plumbers were done and I wish he had called me first. Multiple-step built-up crown moulding with 3 rows of dentiling and around a foot wide ... was pretty much destroyed along one wall. A lot of embossed copper ceiling tiles ripped down all across the ceiling. Plumbers were told to tear out what they had to and fix the pipes, so they did. It wasn't their fault, they did what they were told. The owner was fine with what they had done until he heard my price, threw a fit and said he was gonna get someone else... so I thanked him and left. 6 months later I was fixing it after redoing the estimate and the cost was a little higher. Had another job on a 7 foot by 10 foot room, 12 foot ceilings that had over 10,000 in damages from a tiny leak in the roof and it didn't look that bad at a glance. It was a butler's pantry of a Victorian, so you can think of the room as one huge piece of walnut furniture and the price included resoldering a seam on a copper roof. Those two examples are exceedingly rare and the most extreme ones I can think of over the last 35 years or so, but you just never know what you're gonna run into.
There are also the "special" customers that get charged more. Think of it as a service charge for dealing with their attitude, if you will. I've as much as quadrupled an estimate based on "likely problems foreseen dealing with THAT person" and still gotten the job... even after telling her I knew my price was extremely high and it was because I didn't want to do the job, giving glowing recommendations for my competition that she had also gotten estimates from and were about a quarter of my price. Whatcha gonna do? If they insist, take the money. And nope, I don't feel guilty about it