At the risk of appearing overly polemical:

No, the out-of-India "theory" (OIT) of IE origins has no credibility whatsoever. It's an ideological construct promoted primarily by non-linguists and dilettante historians in overt or covert support of a Hindu nationalist program. It's also inextricably linked with Vedic fundamentalism, anti-Muslim propaganda and, in its darkest corners, "ancient aliens" conspiracy theories. Proponents of OIT often engage in the same kinds of disingenuous rhetorical tactics as creationists, Gish galloping and attacking outdated or strawman positions (especially the long-since-discarded Aryan invasion model) as if they were current mainstream ideas.

Hindutva activists and European ethno-nationalists like OIT because it validates their present-day political agenda, but amongst actual historical linguists both inside and outside of India, the migration model is almost universally accepted and OIT is roundly (often savagely) criticized as amateurish, dishonest, and revisionist.

• Stephanie Jamison, "The Indo-Aryan controversy: Evidence and inference in Indian history (Book review)", Journal of Indo-European Studies 34 (2006).
• Michael Witzel, "Autochthonous Aryans? The Evidence from Old Indian and Iranian Texts", Electronic Journal of Vedic Studies, 7-3 (2001).