[dragonwriter]

> But did semver really set out to eradicate all distinction between minor incompatibilities and complete architectural reboots?

It's explicit terms do, whether or not that's the intent. Backward incompatible is a bright line.

OTOH, I think that exact bright line is the central purpose of SemVer.

[usrusr]

> Backward incompatible is a bright line.

Only as bright as the line between public API and private implementation details that are allowed and expected to change between semver minors. This is not always very clear.