I can't really complain about the worksmanship on my rig. I got what I paid for, no more, no less. Everything works, and I didn't have to haul it back due to show-stopper failures, so I can't complain.
However, with RV wiring the way it is, it really should be a gauge or two thicker than what is strung for the 120VAC circuits. The charger for the batteries is a single stage. The plumbing is joined together by crimp connections. Staples are used instead of glue/screws. Ductwork in the ceilings are either holes in the insulation, or cheap plastic dryer hoses instead of metal air ducts which hold their shape and won't collapse.
A RV maker would have to add about 5% to the price, but use thicker wire, five stage converters, glue/screws, and so on, and the result would be a much more long lasting rig.
Even when installed correctly, sub-par appliances will always be sub-par appliances.
Part of quality is getting the stuff into place. Another part is starting with decent materials and components. You can't get a good apple pie with a pile of good apples and a bad chef, nor can you with a good chef and rotten apples.
So, if I were to point fingers, I'd point at whomever specs stuff out, as opposed to the people installing the items.