What is the point of building so many Jewish museums? There are more of them in the world than you might think: hundreds, possibly more than a thousand even if we don’t count the ones in Israel. The real question is why Jews build so many when so few people visit them. This is not a question that Edward Rothstein addresses in his sweeping and persuasive examination of “The Problem with Jewish Museums,” but it’s one that began to intrigue me as I had the opportunity to visit scores of such museums.