(Person that actually uses sumercé here.)<p>The article is reading way too much into it, and it forgets a very important piece of information:
The origin of <i>usted</i> is "vuestra merced".
Spanish had T-V distinction, like most romance languages,
but <i>usted</i> superceded <i>vos</i> as the formal 2nd person pronoun.<p><i>sumercé</i> is a word that had the same process,
just starting from "su merced" instead, since in Colombia
—like in all other latin american countries— <i>vosotros</i> is not used.<p>That's it.