Yeah IT pros and tech aware "power" users can always take these measures but the very availability of poor or maliciously coded extensions and apps in popular app stores makes it a problem considering normies will get swayed by the swanky features the software promises and will click past all misgivings and warnings. Social engineering attacks are impossible to prevent using technical means alone. Either a critical mass of ordinary people need to become more safety/privacy conscious or general purpose computing devices will become more & more niche as the very industry which creates these problems in the first place by poor review will also sell the solution of universal thin-clients and locked down devices, of course with the very happy cooperation of govts everywhere.