I suspect there are those who have very clear mental pictures of what they want from an instrument, and spend a long time searching for it, and may turn over basses at a great rate.
Myself, what I like most is when basses feel and sound different, and as long as they are capable of being well set up and can be made to sound good through an amp I enjoy the variety.
I find it really hard to understand why people may have many basses that are near identical (Ok I have both Fender and Squier jazz basses but they do feel and sound very different).