It’s marketing. They often do research and calculate the maximum return on investment of their marketing expenditure. Focusing on bass players probably doesn’t make sense for them.
Consider the fact that being a bass player is a bit more “exclusive” than being a guitar player. We are not that similar to them. They tend to focus on all kinds of things we don’t. In my experience, you can pick a random bass player out of the population, and they are more likely to have less gear than a typical guitar player. They are also more likely to be focused on playing in bands and gigging with other musicians. I think guitar players are more likely to be gear heads, collectors, and “bedroom” players. There is also just a lot more of them. I just accept that.
But.....maybe I am way off.