People eat fruit fairly quickly. But, many people sip soda for hours a day which is a vary different situation. Not only do they get acid but the constant low levels of sugar promote significant bacterial growth.

Also, unlike fruit soda has water and sugar, but no nutrients what so ever.

http://www.wda.org/your-oral-health/sip-all-day

http://health.usnews.com/health-news/articles/2012/06/11/5-m...