True indeed. Maybe it came down to a loss of confidence or, at times, underestimating his opponent (eg. the cotto fight). Having or even believing you have fight changing punching power, from what i've noticed, can be as much of a detriment as it is a plus. In, mosley's case as time went on he became too right hand dominant.
You can probably take solace from the fact those people don't know what the **** they are really talking about. Chavez, Lopez, Gonzalez, Barrera, Morales etc all defensively capable fighters/borderline defensive geniuses. Its as though some people on this forum think the only way to be defensive is to bar your body with the left fore arm, keep the right by the chin and roll the shoulder.
LOL. Seriously, they might not have the reflexes and general speed of a mayweather or whitaker, but fundamentally they aren't as far off as some might think.