Green Warp Pipes are Rusted in Super Mario Odyssey
Green warp pipes are all over the place in Super Mario Odyssey, these famous pipes are Mario's preferred method of transportation. However, if you look at the in-game pipe texture, you can see clearly that the regular pipes in Super Mario Odyssey have an uneven rusty texture on the surface - a nice little detail added by the developers. The blocky 8-bit pipes to transform into 2D sections don't seem to have this texture.
Green warp pipe with uneven surface and rust in Super Mario Odyssey
Shiny green warp pipe in Super Mario 3D World
In contrast, if you look at older Mario games, pipes have always had a shiny surface. Pipes in real life are unlikely clean and shiny all the time like they have been depicted in the past. They are usually carrying water or are in areas that have moisture, leading to condensation, which means there's going to be oxidation resulting in rust forming on pipe surfaces.
Or perhaps you can say that Bowser's minions are now just too lazy to do the proper maintenance for the pipelines!