I think you missed my logic for this case. If there would be an update for a kernel-module, and the update has the same Requires: as an existing installed kernel-module of the same name, then replace the installed one with the new one, but don't touch any others that have Requires: for a different kernel.
and I think you missed my point: rpm can't do that.
it doesn't just update a single older version - it updates ALL older versions.
-sv