Individuals do not evolve in the sense that troubles you.  But populations do evolve, constantly creating new expressions of their innate capacity for change.  

And the Church is a population:  The People of God.  This population evolves new means of glorifying God in the saints and martyrs of a particuar age.  

St. Simon Stylites sharpened the understanding of the people of his age with regard to self-denial and contemplation;  he's probably not very relevant to this age, sitting atop his marble column.  

Bishop Romero speaks to this age, as does Mother Teresa.  They are vivid expressions of the evolution of the Church, the People of God.