It's a design problem, not a technical problem.

While PBR material workflows and modern lighting systems have a lot more levers to pull, some of their default approaches give everything a washed out look. The default tonemapping in Unreal Engine also feels more geared to a "Call of Duty" dusty aesthetic than something like Mario.

But I think games like Astro Bot show you can have incredibly stylish, colorful and soulful games today that are actually even more interesting and fun to enjoy when they utilize modern tech to please the player like the haptic controller feedback and tons of physics simulations.