Is it true that the longer you site has been established, the higher it will go up in SERPS. So for example if i have a post on "science equipment", if this page remains the same and small amounts of traffic go there, over time will the SERPS because it is an established page that has been around for a long time, and so the content is probably more reliable. Im stating this becuase a similar thing can be said for old domain names.
it depends on your domain and quality content.its true that u will get promoted if you are old but u also need frsh content on your other site pages to upgrade your old site pages. dead sites dont get updated in serps.