It'd be a different version that's not intended for backward compatibility. This would be beneficial for any new projects or new learners who don't need to sift through decades of changes.

There can still be the standard updates every 3 years for backwards compatibility, but Id assume version upgrades don't happen very frequently. Meaning, if a project is started on c++11 then it's probably going to stay on c++11 indefinitely, never making it to c++17 or some other later version.

If that's true then that would imply in general the projects using c++17 or later are created from scratch using that standard and therefore wouldn't suffer from backwards compatibility.

This is all said as someone who works with Java where I don't see folks migrating from Java 8 -> 11 or later.