The conventional wisdom that gripped the banking industry for the past decade is being upended. Not too long ago, the future of banking was thought to be personal computers, the Internet, ATMs, kiosks—everything but expensive branches. But now bank branches are sprouting up all over the Northeast—more than 200 new ones in New York City in the past two years alone. And for this boomlet, we should thank Commerce Bancorp, the upside-down bank.