Why wouldn't google cloud exist in 5-10 years? The scale of the project isn't the same as google reader or of their other cancelled projects.
Still, for proper context, google reader may be small but google stadia was big by any scale, with significant datacentre investment, dedicated consumer hardware, exclusive publishing deals, marketing campaigns, etc. And 10 years isn't as long as it used to be in the IT world :)
Google cloud (it's earliest form anyway) launched in 2008. It's older than Drive and Photos. In a year or two, there will be Google employees younger than Cloud is.