There is exceptional build quality available in every type of RV class. Almost all of them are boutique manufacturers making only hundreds of units per year. Why? Consumers can't afford that level of quality and workmanship. Part of the problem is consumer expectations. It's the same problem with people buying a starter home but they expect granite counters, whirlpool tubs and home theaters. Something has to give. The highest cost in any business is labor. Best way to hit a price point is to take labor out of the process. That directly effects build quality and workmanship.
People want to buy a trailer for the cost of a sub compact car yet they want a fireplace, an outside kitchen, a residential refrigerator and a 55" flat screen TV. Oh, and they want to tow it with a Toyota Rav4.
This industry only changes when customers stop giving bad manufacturers money instead of getting sucked into amenity rich coaches at a $200 monthly payment.