Why do you assume that what we call humans in the future will be current-day anatomically human? I assume, for example, the ability to run versions of yourself

Why do you assume that what we call humans in the future will be current-day anatomically human? I assume, for example, the ability to run versions of yourself virtually and merge the state vectors at will. Special purpose vehicles designed for certain tasks. Wild genetic, cybernetic, and nanotech experimentation. I'm talking about fundamentally novel superhuman intelligences working with someone who has spent a few millennia exploring what it means to truly be themselves.