Some Advantages of Riding in Group, Beyond the Obvious.
On a ride some time ago, someone’s chain broke. The group was large and stretched out over several hundred yards.
Rider 1 blew a whistle so the whole group knew there was a problem. Rider 2 had a chain tool. Rider 3 actually had a 10 speed Shimano pin. Rider 4 was the only one in the group who had installed and repaired bike chains in real time. Rider 5 knew the route to the rest stop so the bulk of the group did not need to wait on the road.
The only clueless one was the rider whose chain broke.
Or the time there was a crash and blood and one of our group was not only an EMT, but carried a water bottle full of medical supplies.
Or when someone cramped up or bonked miles from nowhere and riders got in front and behind that person to safely ride them back.
Or all the obvious reasons like:
Visibility in numbers. The ability to draft in windy conditions so slower/weaker riders can stay with the group. 12 people who CAN change a flat in 15 minutes or less. 4 riders who do know how to use the barrel adjustment if someone’s gears are not shifting properly.
Of course there is one bad reason, still and forever: unsafe riders.