Horse racing powerhouse the Stronach Group has spent millions of dollars trying to lure younger fans and higher-profile horses to the Preakness Stakes, the second jewel of the sport’s Triple Crown and one of Maryland’s marquee sporting events. It seems to have been a bad bet. Long viewed as the anchor of the state’s storied but declining thoroughbred racing industry, Preakness has gone from a moneymaker to a financial loser in recent years.