Well, Rajput art got Mughal influence well before 1739, during the reign of Akbar (1556-1605) when some Rajput kings signed peace treaties and married their daughters into Royal Mughal family. The loot of Delhi in 1739 had only a minor influence on it. In fact, the Mughal art itself is heavily influenced by Rajput artists. Shahajahan's white marble came from Makarana in Rajastan. The Mughals lost their power and wealth well before 1739, during the long struggle in Deccan (1681-1707) ending with death of Aurangzeb in 1707. He was the last powerful Mughal Emperor who commanded a large army and had wealth to sponsor big artworks (but banned them due to purist islamic beleifs).