If you ever wondered how standards like line level, input impedance, RIAA, or AES/EBU came to be, the first thing you should consider is why. Why do they exist in the first place?
Standards exist to help with compatibility.
Take the RIAA curve as an example. Before the RIAA standard had been agreed to, there were multiple standard EQs: Columbia, Decca, RCA, and EMI, to name just a few. Once the standard had been established, it became easier to choose a phono playback system based not on whether it would work but based instead on how it sounded or the features it offered.
Or, the EBU part of the AES/EBU. Most of us know these letters because they are what we sometimes use to connect our DACs to sources when we want to use an XLR cable instead of a coax. But AES/EBU is actually one of those rare collaborations between two agencies that often set standards to improve compatibility. The EBU bit is the European Broadcast Union, while the AES part is the Audio Engineering Society.
Standards agencies go on and on. Some are useless overkill; others are creating wonderful goals for manufacturers to meet in order to make our equipment play nice together.
Now, if only we had a standard rating system for sound quality.
Think there would be any controversy there?