Comfort and fashion have not been easy bedfellows, but on the hilly streets of San Francisco, pedestrians have found the middle ground. A start-up consultant who I meet for coffee one morning in Hayes Valley is wearing simple shoes from Allbirds – medium-thickness soles, laces that match the body – natch, telling me that San Franciscans are proud to finally be able to wear a home-grown brand. (Them, and Barack Obama, Jacinda Ardern, Eva Chen and Gayle King, who gave Oprah Winfrey a pair and wrote of them: “When shoes feel this good, they don’t usually look this cute.”) Allbirds, founded by Tim Brown, a former New Zealand soccer player, and Joey Zwillinger, a clean technology entrepreneur, is a minimalist line of runners and loafers made from sustainable materials like…