I think one can safely assume that any article containing the phrase "could kill x by changing only y" is worthless drivel. The author has hit correctly on the fundamental difference between the service, but veers into crazy town suggesting that changing one service kills another. I think humans have a replacement bias, assuming that new thing x will replace old thing y, a bias rarely borne by fact. Did planes replace trains? Where's my paperless office? Tools have affordances. If facebook didn't work the way it does, it wouldn't be facebook, and the same for twitter.
More importantly, why, exactly, does facebook want/need to kill twitter?
More importantly, why, exactly, does facebook want/need to kill twitter?