Because switch is winning formula for them. The only reason to bring out a new system is to refresh the machine with newer tech. They reasonably can't make another type of system anyway because they fused their development company for their handhelds and console into one. The switch concept of a machine that does both is the final conclusion of Nintendo hardware as a conceptI didn't remembered the T239 leak.
At the moment the closest model is Orin NX with thermal between 10W and 25W. I don't know if they are counting memory consumption too.
Remove half the ram.
Remove all the automotive specific stuff.
Move from sam 8nm to tsmc 7nm++ and gain 30% just from this.
It's in the switch range but still too much.
Aaaaaaaaaanyway... Why are we all supposing that it will just be exactly like the switch but faster?