devtrackers.gg
So, one thing that seems pretty evident is that everyone lives super close together* so that "time isn't wasted" mentality which kinda puts the likes of Trucks and other Inventory based vehicles a secondary inventory and not a "this will help me travel to other people".
Boats and Trains can aid this as you most likely wont have a boat/train to go like 20 blocks will you. Boats and Trains will enable longer distance traveling which enables more spread out communities or different clusters which also enables larger world sizes to be used.
\At least on the server I play on we basically always live on some form of island together (cause thats what gens on a Small Map) and every rarely spread apart - mainly because we only have a small handful of people playing - like we are enough apart where we can have a decent claim size but thats about it*
On public servers people spread a lot, often way more than they should. It's in opposite much more a problem that people tend to live so much away from each other that it becomes problematic. (But we're actually incentivizing that local community spread with the biome restrictions, as we want them to use trucks to drive to others - I just see people spreading that wouldn't need to as well)