Dolphin on the Steam Deck in an officially supported capacity is likely the concern. That’s a strictly better Switch running exclusive Nintendo games.
It's like Toyota with electric cars, they could have become a leader in EVs as they had the bulk of the hybrid market (and thus experience), but they kept insisting that hydrogen was the way to go despite actual hydrogen car sales being abysmal and EV (read: Tesla) sales exploding.
It's not even a Japanese issue. Every company has this issue, but Nintendo is the oldest game developer. So they get the most flack