As with many things in life, it all comes down to quality. You get what you pay for. A low end new coach will have more issues than a well maintained older high end coach. I've seen a few older Prevost and Bluebird Wander Lodges in my travels and they are still magnificent after 20+ years.
The trouble is the people have gotten lazy and would rather write a check for a new bus than do the research and search for a well maintained older rig. I spent over 6 months looking for the Sahara after researching the line. Then they hit the forums complaining about quality. You never hear from the thousands of people who had no problems or expected issues because they could only afford a low end coach and just dealt with it.