You're talking about 3D World in the context of how it was an answer to next-gen, but by no stretch of imagination was it a success. We were only a year into the Wii U so we didn't know that it was going to bomb LTD. Everybody thought that this Mario would be the thing that saved the Wii U and it not only didn't but got outsold by one of the worst 3D platformers ever made.You mean the Mario that sold on a console that bombed and was always going to sell below any other Mario game yet still managed to pull an insane attachment rate for a 3D Mario? It got then beaten by Odyssey that managed to pull an even more insane attachment rate.
They could have released Odyssey 2 this year and it would have sold way ahead of expectations.
Attach rates are only worth talking about if both things are successful. In this case, neither one was. It's the worst-selling 3D Mario on the worst-selling Nintendo home console. But at least a few people bought them both?