A "fast paced" assembly line to one observer may be an appropriately paced one to another, assuming the line work balancing is done well, and the parts are properly designed and made. As production line are run faster, it often means that the company has to improve a lot of things from part quality and design to employee training. If done correctly, a speed up can actually improve overall quality due to such peripheral improvements. Worker attention and consistency can go up in those situations also, as a worker who has to fight every piece into place, and still have it fit poorly, has very little incentive to be careful, but a worker who sees that the parts fit well, and when put in with attention show quality, is much more likely to do a good job. Good parts, good design, good training, job rotation to prevent injury and burnout, good tools and fixtures, all contribute to good quality.
Of course, if you run the factory like a 1950's sweatshop, with all the blame placed on the workers, you are going to get poor results. It is likely that many of the RV builders are not doing a very good job with their products and assembly lines, based on the quality level we see in many of them.
