There are indeed competent silent cameras from other makes (mainly Sony and now also Canon) but they do not provide similar compatibility and functionality with Nikon autofocus lenses that the Z9 does. As for the move to silent photography, it's not instant and binary but over time it becomes more important as the stacked sensor cameras become more common. Nikon is 4-5 years behind in providing this capability and thus the pressure can be seen in the high interest in the Z9. Mirrorless native lens lineups still lack many items and thus having access to existing DSLR lenses such as 200/2, 300/2.8, etc. can be important to some.