I was giving this thought as I was eating at a local sort of fast food place that does Chicago-style food. Every single person ordered and then sat at their table waiting for the food. The last time we went to Wendy's, we ordered and sat while waiting for our food. In Wendy's case they brought it to us. At McDonald's where I worked for many years, people ordered food while someone got a table, got the ketchup, and all the other stuff while waiting for the food.
So in my somewhat limited work experience in fast food, I would say that the norm is to order food and have someone go sit and find a table while the other person is waiting for the food. In every single fast food place, including Disney, that is how it works. With the exception of some places at Universal. However they have it set up differently so that you can all stand together while ordering and waiting and whatever. Though I will say I needed to sit down, and the cast member was incredibly rude to me. So when you come from a norm of order food, sit down while waiting, then get food brought to table. When someone tries to change it, it feels very strange.
I think the issue is that the parks are a whole different ball game then regular restaurants. The peak times are really the only times that the waits are crazy. It is not unusual to be in line and waiting for your food for 20 minutes. I think what is being said is that during these peak times, if your family is sitting there holding a table for these 20 minutes, then someone who has their food could have used that table and ate and left. If you actually go into these places at lunch time and pay attention to what everyone is doing, you will see that there are many tables with kids sitting there for quite a while while parents are getting the food and others wandering around with their trays trying to find seating. We are really only talking about maybe and hour and a half a day at most. Getting food and then sitting down is not at all strange for many. Those who travel solo or are single adults with little kids have no other options but to do this. Do you never go out to eat alone? And again, WDW counter service restaurants are not like real world fast food places. You can't even compare it to Universal Studios because they don't have the same attendance that MK does. From Theme Park Insider ....
Global Top 20:
Walt Disney World Magic Kingdom, 20,450,000, 0.3%
Disneyland, 18,300,000, 2.0%
Tokyo Disneyland, 16,600,000, 0.4%
Universal Studios Japan, 14,935,000, 3.0%
Tokyo DisneySea, 13,500,000, 0.3%
Disney's Animal Kingdom, 12,500,000, 15.3%
Epcot, 12,200,000, 4.2%
Shanghai Disneyland, 11,000,000, (partial year in 2016)
Disney's Hollywood Studios, 10,722,000, -0.5%
Universal Studios Florida, 10,198,000, 2.0%
Chimelong Ocean Kingdom, 9,788,000, 15.5%
Disneyland Paris, 9,660,000, 15.0%
Disney California Adventure, 9,574,000, 3.0%
Islands of Adventure, 9,549,000, 2.0%
Universal Studios Hollywood, 9,056,00, 12.0%
Lotte World, 6,714,000, -17.6%
Everland, 6,310,000, -9.5%
Hong Kong Disneyland, 6,200,000, 1.6%
Nagashima Spa Land, 5,930,000, 1.6%
Ocean Park, 5,800,000, -3.3%