Yes, being a ladder-frame truck doesn't mean the vehicle will be stiff and uncomfortable to drive. All american trucks like silverado, sierra classic, f150, dodge ram and their suv counterparts like Tahoe, Suburban, Yukon, Escalade, Expedition, Navigator are ladder-frame chassis and super plush and comfortable. Especially Escalade and Navigator. Even their body-roll is less than a Landcruiser. But these xl suvs are just people haulers and heavy loaders. Unlike the Landcruiser and Patrol, not so great offroaders.
It's just how toyota has built the current hilux platform. They focused more on utility and toughness rather than comfort. Landcruiser is a premium toyota brand so they had to keep some differences between hilux/fortuner and Landcruiser/prado.
However, I read in some reviews that toyota has tried to improve comfort in the Fortuner facelift. And moving forward, next generations will be more focused towards premium feel and comfort than the current one.