Clowns at Red Hat do like to break manifest compatibility in the worst way tho, think "a macro with same name in new version now does something else". The idea of .spec file being whole manifest is... nice in theory, not in Red Hat execution. But then last time I did any for RHEL was at RH6/7 time, maybe it's better now...
But even in that case that's fixing few minor things every 3-5 years at worst. There is no excuse to not make your packages if you're actual serious developer, not some random hobbyist.
I do give a pass for apps that run as single binary as that while suboptimal is at least easy to work around.
