Honestly - I think it's trends and marketing; rando is hot now. There are plenty of bikes that make great all arounders and the slight variations determine what is most ideal, but most are plenty suited to 95% + of what they'll be up against. Cyclocross, 80s style sports tourers, XO-1s, converted MTB platforms, full tourers built up like sports tourers...you name it.

For me - these cover pretty much anything they could come up against...