No, most likely, but too much water added and badly managed pouring so dry joints are possible/likely.
That depends on who orders and controls the material, but lower quality glass, non low-e, not toughened etc is possible and hard or very difficult to check. Doors sourced from a maker who doesn’t use correctly seasoned wood or doesn’t store it correctly, very difficult to check as who has the expertise to do so.
If it gets painted it can get bodged
5 spot adhesive not full tile. Paint, thinned too much
A large percentage are labour but as above, sneaked in material can be significant.
But is it mostly labour? Or is it supervision that is at fault? Most likely both.
The takeaway from this is that there are few builders who have the expertise to oversee a really perfect build and the builders to keep it to the highest standard. They certainly exist and you can get lucky to get one who is in the correct stage of his career to give you a really good job.
It is all about luck.
It is certainly possible that there are builders who are professionals and are continuing to build high quality.
The way the society is structured makes the existence of this unlikely as the excellent builder will not be able to maintain excellent skilled workers as the excellent skilled workers can make more money going independent.
The ultimate takeaway is if you know exactly how a build should be done, have the skill to supervise and motivate Thai/Burmese workers can get a quality builder, and can be on site 24/7/365 you can get a house with the minimum of defects