Easy listening-introduced in the 19509 as a sort of calming agent-has fallen prey to the “soft sound”: bland balladeering by Bolton, Gloria Estefan and other pop bantamweights. This mainstream format has a multigenerational appeal that pulls in baby boomers who want something between Megadeth and extended harpsichord solos. But what does elevator music’s death by attrition mean for people who like to hear “Kumbaya” played on the glockenspiel? Well, they can always buy a cassette. Meantime, here’s a telling glimpse of the future: when callers to the National Elevator Industry, Inc. are on hold, they hear Paul Simon.