Isiah 21 refers to Elam destroying Media in the end times. Iran and Arabia.

No, it says that Elam will attack and Media will beseige, nothing about Elam attacking Media. Read it more carefully. Also Media is not Arabia.

The harlot is Mecca.

No, the harlot ancient rome... at least that seems to be the most sensible interpretation to me... see rev 17:9-10:

‘This calls for a mind that has wisdom: the seven heads are seven mountains on which the woman is seated; also, they are seven kings, 10of whom five have fallen, one is living, and the other has not yet come; and when he comes, he must remain for only a little while.

Rome is famous for being built upon 7 hills. Also the 7 kings could refer to:

Julius, Augustus, Tiberius, Caligula, Claudius -- the five who "have fallen" -- the first four roman emperors + julius caesar.

then the sixth is nero, who is probably the anti-christ (hard to say for sure since its all so cryptic) who is famous for persecuting christians.

and the 7th roman emperor only reigned for a few months in "the year of four emperors".

more evidence that the antichrist is Nero:

rev 13:18

This calls for wisdom: let anyone with understanding calculate the number of the beast, for it is the number of a person. Its number is six hundred and sixty-six.

in hebrew numbers represent letters. A transliteration of Nero Caesar into hebrew adds up to 666, or 616 with alternate spelling. interestingly, some versions of the bible actually have 616 as the number of the beast. (of course this could be a coincidence, as there's lots of other ways of spelling Nero's name that would add up to totally different numbers, and probably lots of people who would have some spelling of their name add up to that. )

I also think it's naive to believe that bible prophetic texts actually refer to events in the future, when they could easily be interpreted to refer to events contemporary with the writing of the texts. You're taking the bible way too seriously at that point.