The longer something is thought to exist, the better it is evaluated; happens even with aesthetic judgments of art & nature, that were also positively affected by time in existence

Longer is better. Scott Eidelman, Jennifer Pattershall, Christian S. Crandall. Journal of Experimental Social Psychology, Volume 46, Issue 6, November 2010, Pages 993-998. https://doi.org/10.1016/j.jesp.2010.07.008

Abstract: The longer something is thought to exist, the better it is evaluated. In Study 1, participants preferred an existing university requirement over an alternative; this pattern was more pronounced when the existing requirement was said to be in place for a longer period of time. In Study 2, participants rated acupuncture more favorably as a function of how old the practice was described. Aesthetic judgments of art (Study 3) and nature (Study 4) were also positively affected by time in existence, as were gustatory evaluations of an edible consumer good (Study 5). Features of the research designs argue against mere exposure, loss aversion, and rational inference as explanations for these findings. Instead, time in existence seems to operate as a heuristic; longer means better.

Check also Chapter Two - The Intuitive Traditionalist: How Biases for Existence and Longevity Promote the Status Quo. Scott Eidelman, Christian S. Crandall. Advances in Experimental Social Psychology, Volume 50, 2014, Pages 53-104. https://doi.org/10.1016/B978-0-12-800284-1.00002-3

Abstract: People tend to like things the way they are. All other things being equal, there is a widespread bias in favor of the status quo. We describe two forms this bias may take: people assume that (1) mere existence makes things good and right (the existence bias) and (2) the longer something is thought to exist, the better and more right it is judged to be (the longevity bias). We take care to distinguish existence and longevity biases from other forms of status quo preference. Our research emphasizes people's automatic, heuristic tendency to ascribe existence and longevity to inherent features. We describe how existence and longevity biases contribute to status quo maintenance and political ideology; we also show how these biases provide novel explanatory power for incumbency effects, social norms, and the legitimization of inequality. We conclude with a consideration of exceptions to what appears to be a general rule: people assume that the status quo is good, right, and the way things ought to be.