It's not really a mystery why Russia's mission crashed. Their space program has been struggling to maintain quality across the board. Further, their Soviet legacy was not particularly successful at soft-landing on the moon (7 successes out of 27 attempts).

China has successfully soft-landed on the moon all three times they've tried. India's much lower-budget program has failed twice, but given their success in their other space endeavors, they probably have pretty good odds of making this landing.