I believe smartness is rather contextual. For instance a person might be smart at a specific job like troubleshooting hardware but he'd not be so-smart in some other areas of life. Was Einstein smart in most areas of life? I highly doubt that. This (contextual) smartness is build-up with time. People who have screen-facing jobs tend to get smarter about gadgets/software. People whose jobs are dealing with other human beings gets smarter at soft skills like persuasion. It all boils down to giving enough time.