I think it's largely manufactured. The whole close mystique is entirely engineered and a relatively recent invention in baseball history. And historically speaking through the entire history of the game, he rate at which teams convert what would be a save situation entering the 9th into a win has never changed. Before the use of pitchers in non-injury/performance relief roles, beforeally the invention of bullpen specialists, before the invention of the save as a statistic, before the invention of the close as a singular job or he rigidly structured 7-8 man pen, and since any and all of those things, if you enter the 9th with a 1-3 run lead you're bounder to win those games about 95% of the time no matter the date of the game. If the last 3 outs were any harder to get than any other outs for any objective,rational, and non engineered psychological reason, then the rate shouldve changed at some point.
But it hasn't.
I wish I could still find a post I made about this where I linked the study and article that info came from. Several years ago I made a post in a Blue Jays thread about why saves are stupid and the close is overrated and cited that material. But I think it's since been lost to the great thread purge that nuked anything older than roughly 3 years.
EDIT:
I don't have that post, but I have some links that I believe point to the same evidence (the original ESPN piece that had some extra work tied to it seems to have been nuked in one of ESPN's reorganizations of their site.
http://mlb.nbcsports.com/2014/04/30/the-timeless-game-and-maybe-the-myth-of-closers/
http://tangotiger.com/index.php/sit...leading-into-the-ninth-means-winning-the-game
http://www.retrosheet.org/Research/SmithD/ScoringPattern.pdf
