As somebody who manages a piece of software often used in wii modding: ye, do it! Mod a wii :p

But seriously, the ps3/wii/x360 were the last gen where the hardware design was rather simple and easy to understand, making it fun to play with and learn. The wiiu ended up with a bootrom making it harder and way more complex to run your own stuff on it ( outside of wii-mode and non-system menu stuff ). Then the switch was a whole new level (and we got lucky there with the bootrom exploit).
Switch added secure bootrom, executable validation, firmware blobs, no-execute memory flags, dedicated crypto hardware in cpu with it’s own firmware, …
Even if you had raw access you still needed to implement some stuff just get hardware even going.