Not aware of the full history.
We have limited resources to work on exporters and datasmith in general. So we had to make choices over time on which software to prioritize based on community usage and needs as well as existing alternatives between the software and UE.
We are reviewing existing pipeline between Maya and UE. USD is a reliable route at the moment.
Evaluation is still ongoing but the added value for a dedicated udatasmith exporter does not look that important.