Rokket, in practice, the aircraft ID part of VHF comms doesn't take up that much airtime. In talking to ATC, it's the reading back of all crucial bits of clearances/ instructions that takes time. And in the case of CTAF (pilot to pilot) chat, it's trying to clarify position and intentions - generally self separating - that fills up the frequency. And actually, in CTAFs, I reckon it can be useful for the ID to be said again at the end, along with the location. (It can obviate a heap of "Say again call sign" type calls.) Also, at ATC's discretion, call signs can be shortened to handles that take a second to say. For example, in this short vid, soon after "Sportstar 9696" has established contact with Tamworth tower his call sign is cut to "ninety-six, ninety-six".
But yeah it's a long-in-the-tooth, legacy system which will, I reckon, be overhauled by new ways and means before it's seen as practical to reform it.
https://www.youtube.com/watch?v=gXukpQlRhnM&t=31s