RSS readers allow you to collect the articles of specific sources in one app, making it a lot easier to find the content you’re interested in without crawling through a lot of noise. RSS (which may stand for Really Simple Syndication, Rich Site Summary, or one of several other possibilities — nobody seems sure) has been around a while, having been first developed in 1999, although it wasn’t more widely adopted until a few years later.
Thanks for the summary! More articles should be concise and more “complete” (e.g. mentioning alternatives like NetNewsWire or Vivaldi’s integrated RSS reader, as mentioned in other comments here).