Home prices have hit record highs in some major U.S. metropolitan areas, and house-flippers are behaving like it’s 2005: [...] residential real estate isn’t in a speculative bubble, industry observers contend. “The havoc during the last cycle was the result of building too many homes and of speculation fueled by loose credit,” said Jonathan Smoke, chief economist at Realtor.com. To illustrate his point, Smoke compiled an index based on six factors he deemed crucial to the housing boom and bust of the mid-2000s, including price appreciation, the prevalence of house-flipping, and share of buyers who used mortgage financing. [...] the share of U.S.