Over the past few decades, as the value of sports franchises has exploded, ass-covering local politicians have learned to model a familiar behavior any time one of their teams tries to whip up fervor in support of a new stadium: Publicly balking at any suggestion that public funds be used to build an arena for a billionaire owner. “Chicagoans love the Bears,” they’ll say, “but not enough to support deploying taxpayer dollars for a new stadium.” And local voters seem to mostly agree: A year ago, Kansas City voters soundly rejected a tax increase that would have been used to refurbish Arrowhead Stadium (home of the Chiefs) and Kauffman Stadium (the Royals). A year prior, Tempe voters rejected a taxpayer-funded arena to keep the Arizona Coyotes in the state. Earlier this month, San Francisco Giants C.E.O. Larry Baer candidly discussed his team’s do-or-die private financing journey to move the team from the dregs of Candlestick to a waterfront ballpark downtown.