If I'm getting it right, and if I can extend the findings to perennials (grass in particular), this adds another reason to "just let the grass beat out what you don't want" tenet of the lawn care article. In competition the grass may "bulk up" root-wise much more than if it was extending out into empty space. You could even personify and have it make even more sense: Since it had to fight for the space, the surviving/winning grass is that much stronger.
I'm liking [non-alleopathic] weeds more and more! "What doesn't kill my grass makes it stronger." Heh.