You say your repository has over 70K files but fossil is only showing
12536 artifacts and only 55323 files.  If some of the files are duplicates
of one another, then the duplicates will only count as a single artifact
and so that would explain why the artifact count is much lower than the
file count.  (Please confirm that the project contains many duplicate
files.)  But Fossil's file count should be accurate and 55323 is less
than 70K.  Are you sure the initial check-in worked?