The U.K.'s Guardian assembles some experts to predict. Some are plausible; some are not. This one, from an executive at Ogilvy and Mather, made me laugh:
In 25 years, I bet there'll be many products we'll be allowed to buy but not see advertised – the things the government will decide we shouldn't be consuming because of their impact on healthcare costs or the environment but that they can't muster the political will to ban outright. So, we'll end up with all sorts of products in plain packaging with the product name in a generic typeface – as the government is currently discussing for cigarettes.
(The man knows how government works.)