The Popperian question ("What evidence would it take for you to change your position?") would be wasted on some. Today's LA Times editorializes on the importance of more subways for Los Angeles ("Westside's second chance"; am not able to link for some reason). They are pursuing the same logic that they have been using for half a century: build it and they will come.
In the process, Times writers have treated their fellow citizens to a very expensive real live experiment. Billions of dollars have been spent on rail transit for L.A. and there is nothing positive to show for it. In fact, overall transit use is down, red ink is up, and blight along the Red Line's route is advancing. The Ambassador Hotel site is rat infested and the Miracle Mile's premier location (at Fairfax) now features a 99-cents store outlet.
There are opinions held and opinions upheld. But opinions held with no supporting evidence whatsoever (and when there are large sums of other people's money at stake) reveal a spectacularly blinkered ignorance.