I would love to see footnotes very soon. However, it is sadly normal that footnotes are implemented rather late in DTP applications: QuarkXPress seems to have introduced them only in their 2015 Version, almost 30 years after its launch. Adobe InDesign gained to support footnotes in CS2. InDesign not have a proper endnote feature up until CC2018.
So, while it is frustrating that the feature is lacking and while many understandably need this feature for projects, it is not unusual to see them not included in the essential feature set for a DTP software’s launch and first years versions, even. The prototypical use case for DTP software seems to be magazines or posters, for which other features are more essential.
Highly structured documents (which is also what I would love to use Publisher for) seem to be a tricky market, being under pressure by quite decent word processors as well as proprietary typesetting environments and LaTeX.