Good post Lemmy...
Another thing many people don't bring up when this type of thread comes up, which is often, It also can depend greatly on how long it takes for you to submit. Some people have it down to a science and can submit very quickly so submitting to more sites, for them, is not as time consuming as it may be to another webmaster. For another webmaster, submitting to another 50 or more sites, might take more time than it is worth. We only have some much time in a day.