Probably unfair take of me, but I don't the video shows the actual process. I don't believe you can get the precision needed by doing it like this video shows. I think something else is happening off camera.
of course there are also pre-made metal parts (possibly also hand made, but needing a small lathe), but the PVC tracing, cutting and gluing looks entirely real.
I don't say it is impossible, not at all. But I question if it is completely made by hand like shown in the video, or if there perhaps are CNC machines or laser cutters to help, but not shown. For example, the holes line up so well even though they are hand drilled. I wonder how he can achieve the needed precision with just eye measure.
It seems entirely genuine, and yes, it is possible to be very precise with just eye measure/hand held tools, which does not mean that it is not difficult and a lot of experience is needed (i.e. it is not something that anyone can do).
Source: something very like this was my father second job from the '60's to the '90's, while the largest part was architectural models (buildings) he made also quite a few "mechanical" models (not in PVC, mainly in wood and/or tin/metal, though perspex/plexiglass was also largely used).
Comparably complex/detailed projects were only a few ones that I can remember, because the cost (number of hours needed for this kind of builds) was rarely affordable by the customer.
I remember (in the late 70's or maybe early 80's!) a model of a set of solar panels mounted on a circular rail that could tilt and rotate to follow the sun, fully working (a strong lamp was used to simulate the position of the sun and the model "followed" it).
Still all he had in his workshop were three or four small table saws, a couple alternating ones, three or four electric drills, a small electric router, more files, planers, pliers and manual tools than you can imagine, some soldering irons and little more.
I often helped him after school, I was usually tasked to make "repetitive" (simple) pieces, he would prepare a sort of template and/or show me how to make the specific little component and I would then make them or help him with assembling the more complex ones.
While watching I was comparing the entire build to 3d printing. More specifically the process knowledge gained doing this in CAD and then 3D print vs handy making parts from PVC.
Everyday uses for PVC water pipe - https://news.ycombinator.com/item?id=37528472 - Sept 2023 (136 comments)