(aside)
I ask this question (and other questions like whether SRPM
installs should be tracked) periodically, have for years.
This bug report triggers the duty/obligation to ask Yet Again:

      https://bugzilla.redhat.com/show_bug.cgi?id=499239

Obsoletes: are applied once, when the package that carries
the Obsoletes: is upgraded.

Basically that leaves a back-door where a later install/upgrade
of the Obsolete:'d package(s) is permitted. The issue is periodically
re-discovered and invariably leads to
	RPM sux!
conclusions.

The proper "fix" is to make Obsoletes: persistent like Conflicts:,
with a semantic that any Obsolete:'d package added to a transaction
is automagically discarded (with or without warning with all the usual
enablers/disablers for the warm/fuzzy bikeshed discusssions).

Should I make Obsoletes: in RPM persistent?

no opinion == no implementation, I'm a lazy/busy schmuck.

73 de Jeff