Yes, those two pros do pretty well by hitting big groundstrokes at their opponents.
My experience at 4.0 ladies is that a strategy of blasting at the bodies or feet of two net players won't work. The average 4.0 lady cannot hit the ball hard enough or with enough topspin consistently enough to beat two decent volleyers at net.
Did you notice how Mark Lopez could run to and set up on the volleys his opponents hit and hit a second awesome groundstroke? Not gonna happen at ladies 4.0. Hitting that second groundstroke off of someone's volley is very difficult, especially if it needs to be high quality.
-- Random Error Generator, Version 4.0
-- Master Moonballer