Just nine months ago, Masayoshi Son publicly declared Ritesh Agarwal one of the star entrepreneurs backed by his SoftBank Group Corp. The Japanese billionaire boasted that Agarwal’s Oyo Hotels & Homes was poised to overtake the biggest hotel chains in the world just a few years after its founding. “It’s unimaginable,” Son said on stage at SoftBank World in Tokyo. “At 25, he’s going to be world’s biggest hotel king.”