I'm calling it right now. Develop world costumers are increasingly seeing smartphones as limiting rather than empowering. It will shift into a product for areas with poor infrastructure as higher income push back against this invasive and manipulative technology. This will create a feedback loop. Lower average income will drive down the utility of the platform for those who fund it (advertisers), smartphones will gradually lose their status signalling value and in another generation it will be prevalent only in areas with poor infrastructure.