I think part of it was also how long the G.I. Generation stuck around. At the time when you'd expect to start seeing Silent presidents, Reagan won election as the then-oldest person to have ever been elected president and was popular enough he had two terms and got his VP elected afterwards. If Reagan's first term had flopped (or maybe even if he'd never run at all, though that's really speculative), we would've gotten President Mondale in 1984. Or we might have seen a Silent as early as 1980 if Ted Kennedy won his primary challenge.
I think we're starting to see a similar phenomenon with Generation X being pushed out by long-lived Boomers and even a couple of Silents, but at least we had Obama (born 1961, so he barely counts) in between Boomers.
With that said, it's not for lack of trying that we haven't had a Silent president. Aside from the aforementioned Mondale and Kennedy's attempt, we've also had Michael Dukakis and John McCain as major-party nominees, the only third-party candidate who had a chance in Ross Perot, plus Bernie Sanders was a major contender and runner-up for the Democratic nomination twice.
I think we're starting to see a similar phenomenon with Generation X being pushed out by long-lived Boomers and even a couple of Silents, but at least we had Obama (born 1961, so he barely counts) in between Boomers.
With that said, it's not for lack of trying that we haven't had a Silent president. Aside from the aforementioned Mondale and Kennedy's attempt, we've also had Michael Dukakis and John McCain as major-party nominees, the only third-party candidate who had a chance in Ross Perot, plus Bernie Sanders was a major contender and runner-up for the Democratic nomination twice.