The main problem is that it is generally believed that Iran was just the land of Elamites and Iranian-speaking people but this country was actually the land of Indo-Europeans.
For example we know Geneva in Switzerland and Genoa/Genova in Italy has the same Indo-European origin:
https://en.wikipedia.org/wiki/Geneva
"The city was mentioned in Latin texts, by Caesar, with the spelling Genava,[26] probably from the Celtic *genawa- from the stem *genu- ("mouth"), in the sense of an estuary, an etymology shared with the Italian port city of Genoa (in Italian Genova).[27][28]"
What about the ancient port city of Genava in Iran?
https://en.wikipedia.org/wiki/Bandar_Ganaveh (in Iranian language it should be Zanua)
Or we know the names of Celtic Brigantes and Germanic Burgundi tribes have the same Indo-European origin:
https://en.wikipedia.org/wiki/Brigantes
What about Birgandi people in Iran?
https://en.wikipedia.org/wiki/Birjand (in Iranian language it should be Berezaiti)
Or we know the names Italic Samnites and Germanic Semnones tribes have the same Indo-European origin:
https://en.wikipedia.org/wiki/Samnites
What about Semnani people in Iran?
https://en.wikipedia.org/wiki/Semnani_people (in Iranian language it should be Hamnana)
The name of Germani people was first mentioned by Herodotus as an ancient people in Iran, the name of Gaeli people was first mentioned by Pliny as ancient people in Iran, ...