For software updates without updating the distro, backports can be turned on.
The reason that everything is packaged together like that is so library updates and other things can be tested and vetted for compatibility. Part of the challenge of allowing such a variety of OS and system configurations is that library or software package maintainers are unlikely to have tested their updated code on every possible distribution out there, and so that makes it the responsibility of the distro maintainers.
Believe it or not in practice this doesn't create many issues. It might be an obstacle for casual users who are trying to transition into power users, and are trying to tweak their system. But most other users aren't encountering the same frustration.
The reason that everything is packaged together like that is so library updates and other things can be tested and vetted for compatibility. Part of the challenge of allowing such a variety of OS and system configurations is that library or software package maintainers are unlikely to have tested their updated code on every possible distribution out there, and so that makes it the responsibility of the distro maintainers.
Believe it or not in practice this doesn't create many issues. It might be an obstacle for casual users who are trying to transition into power users, and are trying to tweak their system. But most other users aren't encountering the same frustration.