It actually amounts to the same in real life. There are a lot that prefers fixed positions the same as switches, you'd be surprised. As for in BL, it's more to personal taste from the authors themselves.
I'll only read the manga if I like the art unless the plot is that great that it supersedes the art. Some of my favorite yaoi manga authors: Kusabi Keri, Sachimo, and Takarai Rihito.
I dont understand why switch couples in BL are rare when its common in real life. Im rooting for Rakhyun to top even just once.
It actually amounts to the same in real life. There are a lot that prefers fixed positions the same as switches, you'd be surprised. As for in BL, it's more to personal taste from the authors themselves.