People are asking for an explanation of the "5-hour gap" because it's one of the central points of his contention that Sunday is a rip-off. They arrived at the vendor hall at 3, shocked, SHOCKED! that they only had an hour left, and that it's somehow Gen Con's fault. Something that a quick check of the website would have told them.
It seems like they just showed up at 10 with no pre-planning, wondering "OK, what do we do now?" Yeah, in that case, they're going to have a crappy experience, but that's no one's fault but their own. If I'm dragging 4 kids to a crowded event, I'm definitely going to have a plan to keep them occupied & engaged, not just wandering around looking for things to do.
There were a number of free Demo events Sunday, but yes, other events add expense, something else that planning for the trip would have told them.