It has to do more with familiarity, or perceived familiarity on assumption of an audience, than you might expect: get ready to be slightly appalled/offended.
Historical films will either have to unpack the contextual circumstances of an event or assume a preformed familiarity the audience has brought with them. Hollywood assumes a typical cinematic audience of 18-25 year old white males. That's not an accurate reflection, and there are thousands of examples where films aren't made for this demographic, but those films are typically crafted against this audience in order to court another: even when it's being fought against, the demographic is still recognised.
So if a film producer is trying to appeal to this demographic, they could support their project with as many pre-circulated paratextual material as possible: basically, if someone has a vague familiarity with something, they will apparently be more likely to engage with it.
Most white Americans are from European colonialist decent, and as such will take Judeo-Christian and Roman/Greek European mythology as the etymology of most of our fables and cautionary tales... western stories are built on these memes: Christ-like messiah, Cain and Abel, Hercules...blah blah blah.
Even when not recounting these stories directly, we are largely circulating updated and modified variations of them. They are infinitely familiar and woven into the cultural identity of western entertainment...
... It has been posited many times before how Asian stories differ from Western ones in style, structure and content. Linguistic theorist Claude Levi Strauss is noted for declaring that Mythology is a language, and is vital to how cultures communicate both with themselves and with others... from this perspective, asking why Hollywood doesn't make Indian epics is similar to asking why Hollywood doesn't produce films in Gujarati: it's clearly not the audience they are trying to reach, nor would it be profitable in the north American market.
There is something sour about the introverted way Hollywood has to recycle itself: there is yet another Hercules movie coming out this summer, when we've already had a slew of derivations of the same character (Conan being chief amongst them)...
... for a country with a huge diaspora, not to mention a significant African American population, it is odd that we haven't seen a great deal of internationally derived output. Films like Crouching Tiger, Hidden Dragon are capable of crossing this divide: but it must be pointed out that this movie itself was produced and directed by a Taiwanese director already deeply entrenched in the Hollywood system...
In answer, its unlikely we'll see any Eastern/Indian inspired cinema until Western civilisation inherits a familiarity with such cultures and traditions, experiences a sudden 'Crocodile-Dundee' infatuation with a country very quickly or until more movies are made that create a cinematic precedent for the area to be explored: it will also take a significant amount of persuasive Indian personalities on film boards to lobby and campaign for this...
...Whilst Bollywood still exists, and has the Indian film market tied up, what would be the point in competing with Hollywood audiences, at least from a financial perspective?
It is my deep desire to see Mahabharata or Ramayana made as movies ...
Beware of your wishes: They will probably come true.