Australia- never needed a plunger and unless your house is 70+ years old, the cistern and pan are always close coupled.

That said, for a Toilet the sewer connection is 100mm DWV and we use washdown toilets (as most of the world does) vs. American siphon toilets, which use an absolutely massive amount of water and a tiny little trapway to create a siphon that sucks the waste down - that tiny little trap is what gets clogged.

I think Americans would probably sooner move the Metric system than change to a better pan design.