Earlier quoted context omitted.
It's only a contradiction if you think short term. Long term, it's clearly in Google's interest to engender sustainable consumption. People who are comfortable with the role their smartphones play in their lives are much more valuable consumers than addicts who are apprehensive over it. They are also much less likely to seek radical action which may damage Google in hard to predict ways.
It has not, historically, been in the nature of companies to think or act in the long term. People inside companies have incentives to bring short term profits, while long term profits benefits only the company as a whole, not any individual internal actor who may be positioned to make them happen. Therefore, they don’t happen, and large organizations basically always act only in the short term.
It's things like that which motivated Henry Ford to pay his workers are more fair wage than his competitors.
Google's founders still control either the majority or a large plurality of the voting stock, so they can have the company align with long-term profit motives, and sustainable existence.