Marketing ventures such as its recent tie-up with SONICblue will not be enough to reverse Coke's recent poor fortunes, according to a report by industry analysts, Datamonitor,. The venture, producing co-branded digital audio players, is aimed at improving the brand's image among young consumers. But on its commentwire.com service, Datamonitor contends that with earnings in decline since 1998, Coke must increase investment in the more profitable non-carbonated soft drinks markets.