I am not sure whether by "all historical updates" you are only referring to all
updates being listed in updateinfo.xml, or all history generally (including old packages).
But in the latter case, note that keeping all updates massively inflates the storage
requirements for maintaining a copy of the repo, which many (or even most) corporate users
do. This is not a huge problem, generally, but it's also not ideal, and probably
isn't the right tradeoff for Fedora.
Here[0] for example is RHEL 8 baseos and appstream, for which the difference between
storing "only the latest package" and "all the packages listed" is 20x
and 10x, respectively. Metadata size would likewise be larger, meaning DNF clients have
more to download.
[0]
[dalley@thinkpad repos]$ rpmrepo details el8-baseos
...
Number of packages: 12910
Number of unique packages (latest version): 1798
Number of packages (latest 3 versions): 4459
Packages total size: 23.82 GB
Packages total size (latest version): 1.4 GB
Packages total size (latest 3 versions): 4.03 GB
[dalley@thinkpad repos]$ rpmrepo details el8-appstream
...
Number of packages: 29103
Number of unique packages (latest version): 5902
Number of packages (latest 3 versions): 12988
Packages total size: 92.91 GB
Packages total size (latest version): 9.12 GB
Packages total size (latest 3 versions): 23.91 GB