Uh, okay, along what lines?
The logical outcome would be two sub-species, “gracile” and “robust” humans similar to the Eloi and Morlocks foretold by HG Wells in his 1895 novel The Time Machine.
Now I am laughing. He thinks our over-dependence on technology will lead to this? Look at yourself, Mr Curry: we have no claws, no fur, no fangs. We’ve been dependent on technology since we first were human.
And who’s to say, if only two clades emerged, that the short ones wouldn’t ben the geniuses, who shortened themselves to maximize energy usage and extend lifespan, while the big tall ones aren’t the biological SUVs of the future? Mr. Curry doesn’t get it. Doesn’t get how powerful our tech is becoming, how we’re going to be engineering immune systems and shaping our bodies consciously in the future… and not such a distant future at all. He should try reading some SF more recent than HG Wells, I think.