It's arguably not "negotiation", but if the connector is USB-C on both ends, then even 5V requires a couple of resistors to determine which side is the source and which side is the sink.
It's pretty common for really cheap electronics to skip these resistors, and then they can only be powered with a USB-A to USB-C cable, not C-to-C. (Because USB-A ports always a source and never a sink.) Adafruit even makes a $4.50 adapter to fix the issue.
But you're right that everything higher than 5V & 3A gets significantly more complex.
All correct and agreed.
My comment was in context of the active communication between source/sink on USB-PD and the increased complexity, intentionally excluding passive configuration using different resistors.