Regarding Jinder Mahal's current main event push on the SmackDown brand, the main reason for the push is WWE's hope for growth in India.
WWE has more social media followers from India than any other country and India is the #3 country for TV rights fees but they are not making a lot of money in the country right now. Like they're planning on doing in China, WWE is hoping to cash in on their popularity in India.
No word yet on if Jinder will defeat WWE Champion Randy Orton at Backlash next month but Dave Meltzer noted on Wrestling Observer Radio that WWE officials are looking to get the stable with Mahal and The Singh Brothers (The Bollywood Boyz) up and running. There's also potential for WWE NXT Superstars Jeet Rama and Kishan Raftar being put with Mahal and The Singh Brothers. As noted, WWE had The Singh Brothers, using their previous gimmicks, accompany Jeet to the ring for a dark match at last week's tapings.
It's possible Jinder is just another bump in the road for Orton as original plans had Baron Corbin bringing his big top-heel push to the WWE Title chase.