The architect isn't present at all times. When I paid a company to put some new flooring, paints, etc a few years ago, the interior architect told the guys "the floorboards must always be placed in the direction of light, from the window wall towards the opposite wall". The following morning, I came early into the room, and the guy was dutifully aligning floorboards in the wrong direction. "What are you doing? You're supposed to lay them this way, not that way" "Oh, just testing". My ass. The guy had already forgotten the instructions he received the night before.
In the toilets, the painter dutifully painted shut the plumbing and valves access panel ("you must open the panel before painting everything. And please don't paint the valves"). The electrician was about to pierce a hole between floors 1 foot away from the walls to pass cables through as I stopped him. Etc.
When having an house built, you (or the architect, or some other responsible person with a working brain) must be there looking at everything all the time. And even with that, they will fuck up. They'll lay alternating tiles in the wrong pattern. They'll build stairs of uneven height. They'll put a window in the kitchen that won't open because it hits the faucet. They'll set up doors that open on the wrong side (all of these happened to my in-laws when getting their home built, and they were there watching every day). They'll fuck up every time you don't watch, every single time.
In the toilets, the painter dutifully painted shut the plumbing and valves access panel ("you must open the panel before painting everything. And please don't paint the valves"). The electrician was about to pierce a hole between floors 1 foot away from the walls to pass cables through as I stopped him. Etc.
When having an house built, you (or the architect, or some other responsible person with a working brain) must be there looking at everything all the time. And even with that, they will fuck up. They'll lay alternating tiles in the wrong pattern. They'll build stairs of uneven height. They'll put a window in the kitchen that won't open because it hits the faucet. They'll set up doors that open on the wrong side (all of these happened to my in-laws when getting their home built, and they were there watching every day). They'll fuck up every time you don't watch, every single time.