I think the confusion stems from a conflict between my definition in the article (reason is time spent thinking) and some of the more common, but less precise definitions (reason is the output of thinking time, or reason is the efficiency or effectiveness of thinking time).

Under the definition that reason is time spent thinking, if you don't spend it by thinking about something, then that time wasn't reason at all, so it's 'lost'. This is different than spending time thinking but failing to produce any output.