Your point of lack of true craftsmen these days is dead on.I will tell you my first hand experience
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My Dad is a retired brick mason. My whole family two generations back were masons. I worked with them all as I was coming up and learned many valuable lessons. One of the major things was the time and care they took building fireboxes and chimneys. They would lay out the whole firebox on the floor and precut the fire brick at precise angles front to back and the fit with the sides to back. Only after they worked everything out right on the floor would they build it.They would also put a little roll or rounding to the back of fire box to smooth the flow of smoke and make it draw right.
The damper had to be set at the right place and height in the box to make everything work and the flues would be set and the transitions smoothed. No air gaps were left anywhere outside of the firebox and flues. It was filled solid from the foundation to the top of chimney except for the firebox opening. The top had to be so far above the roofline and capped off a certain way.
I have seen them refuse to build a fireplace for contractors who wanted to take shortcuts on the fireplace to save money as these are very expensive to do right and my family had seen houses burn from bad work
My dad still takes a few small jobs at times. Most of them involve a firebox that wasn't built right or needs to be rebuilt. True craftsmen are hard to find ... few are left anymore.
They weren't willing to take chances with the heat and carbon monoxide from combustion and I will not either.
My great grandpa and grandpa were carpenters. While I'm nowhere near the skill, ability, or precision that my grandpa was I do notice and appreciate good woodwork. And even the high end homes these days rarely have the fit and finish that his house did.
One guy in our area (a real quirky dude but that's a side story) does trimless carpentry. His apprentice did my sauna paneling and its absolutely top notch. Slow but beautiful.