And even if you develop the perfect archive format that happens to nail every possible use-case 100% (which you won't, because there just are too many), you will STILL have to deal with compressed and archived artifacts which accumulated over the last six or so decades in various places.
That's a parallel universe far far away, ~99% of people having to use tar (just because it's the standard and the only format supporting links/access metadata) every day will never have to use a tape drive. I don't see a reason why we can't use 2 separate formats - one for everyday packaging, a different one for tape drives.
> And even if you develop the perfect archive format
There is a perfect format already - it's 7z. Just add file access rights and links support to it. No need to invent anything really new.
These two sentences seem to contradict each other.
By the way I have just found an actual imperfection in 7zip: it can't let you choose the order in which archived files are stored in it nor chose different compression parameters for specific files. This limits its applicability. E.g. the EPUB standard says the first file in an archive must be "mimetype" and it must be not compressed. But I believe this can be fixed with reasonable ease (and probably without breaking changes) as well.