I'm one of those guys who insists on a smooth car-like ride on my coach. Of course, I drove 27,000 miles on my last gasser coach in 3 years and I already have 13,500 miles on my new DP coach in 10 months so I think I drive more than the average poster on this site.
On my gasser, I had to align it, adjust the tire pressures, do the CHF, get air bags and sway bars to make it ride the way I wanted to. This made me very happy and I enjoyed learning about the suspension. Not everyone is like me and that's OK. People value different things.
But to answer your question about how this happens, there are several factors. The coach and the chassis are manufactured by two different companies. The F-53 chassis builders do not know what configuration and weight will eventually end up on the chassis. This makes it impossible for them to optimize the suspension. The coach builders take a more or less hands off approach to the chassis. They don't want to hurt your warranty and most buyers simply do not care or don't know any better to demand better.
Go ahead and take the plunge. Once you get the tire pressures correct, do a four corner alignment, and the CHF, you'll probably be 75% of the way towards a nice ride anyway without spending much money at all.