When first starting b&w work, I didn’t intend to make landscapes. I wanted to concentrate on types of image that needed monochrome to work, and wasn’t at all sure that after years of working at colour landscapes I’d “see” a b&w opportunity. But I guess it just crept up on me.
When using film, I tended not to shoot the same scene in colour and in b&w, so most of my monochromes were a decisive choice in favour of b&w, made before exposure. In general I was happy with the choices I made, and it was rare that I had any regrets afterwards. I can look at my collection of b&w prints without thinking "I wonder what that would look like in colour".
Digital cameras changed all this since you don't need to commit to colour or b&w until after exposure, and have the chance to think about it afterwards and explore options. I do still generally have a very clear conception of whether the photograph will be colour or b&w before exposure. But now I can change my mind after the event, and sometimes - to my surprise - a photograph I expose thinking *colour* ends up as b&w. The reverse is rare.