You may perhaps not realise - that iNat curators are volunteers. And not necessarily all qualified as your ‘experts’.
There are issues around some iNat taxonomy problems - which are locked to a particular curator. (I am not a curator, but have tripped over some of the problems)
https://forum.inaturalist.org/t/require-a-comment-when-adding-a-coarser-id-to-an-observation/45736/5
https://forum.inaturalist.org/t/how-to-respond-to-comments-by-experts/27819/6
https://forum.inaturalist.org/t/general-consesus-on-being-asked-to-fix-ones-id/14609/19
https://forum.inaturalist.org/t/identification-tips-for-ids/29796/21
and there are many more
https://forum.inaturalist.org/search?q=explain%20reason%20for%20ID
Meanwhile we have piles of Unknown and Needs ID. Identifiers chose where they prefer to put their effort. Whether expert, or not.