This will be so because polytheisms see divinity as an expression of eternal truths which repeat in different forms while monotheisms see it as an expression of a set of historical events which terminate after their existence. https://twitter.com/indianhistory0/status/1390354459482476544

This manifests even in human-divine interface matters such as finality of prophecy which is a strong feature of monotheisms (since the only proper ones we know of are Abrahamic)

This is an important point of difference as well, if one exerts oneself to recognise it.
There are other things too
1) Uncreated eternal soul
2) Two way flow between mundane and divine realms.
3) Evolution of ritual spaces as needed

and so on.

I had made a not so comprehensive list of differences https://twitter.com/pinakasena/status/1346159498696790027

*occurrence
Distracted mistype