Nintendo Switch 2 Motherboard (Why only 12GB RAM?)

On the leak motherboard, it shows 2x6 GB LPDDR5 for 12GB RAM.

So why can't creators boost it to 2x8GB for 16GB RAM total?

I'm not a expert in mechanical technology but I know technology on Switch2 is neatly 3-5 years old so I wonder why can't they add 16GB RAM?

Since 16GB RAM have been around for a long time and there are some models that are pretty old so finding a batter and cheaper model one should be easy right?

EDIT: I forgot the cost please