Because solidworks is the gold standard in the space and is intuitive for millennials that grew up on computers. It mirrors other software that came before in terms of super basic stuff like how to draw a damn line. If you’re going to do a big swing and change the paradigm with a fundamentally better way, it better be really good for a really good reason.
I also prefer to move the camera, which a mouse is more intuitive for. A 3d mouse is like holding/rotating the object. A middle mouse button is so freaking simple and fast I just don’t understand the problem. Moving the view around is like 2% of my workflow.
And scroll up has to be zoom in. The fact that many defaults are the opposite is literally insane.