Not disagreeing, but: Bass reflex designs are an exception to some of what you've written. They essentially use the reflected sound wave you've mentioned to increase the output in certain low frequencies, by letting it out of a specially constructed hole in that solid cabinet.
I'm sure that you're using simplified terms to explain this but bass reflex enclosures don't use reflected sound per se. It's a heimholtz resonator(like blowing across the top of a glass bottle) and the air in the port is in phase with the front of the speaker until it's tuning frequency at which point it rolls off more steeply than a sealed enclosure because of phase cancellation.
