If we are talking about software players, it is obvious that they work under the limitation of the OS API and cannot jump out of this "sandbox" when transmitting signals to your audio devices. At least, if the software player developers do not provide their own drivers for the audio interface (for example, ASIO).
Writing a driver and installing it into the system requires digital certification (approved by the OS hardware team, such as WHQL), so it's much more difficult for developers, and generally unnecessary, to create the bit-perfect software player, since the OS can provide API with all the features , which developers require to achieve the same goal without a special audio driver. As for me, it is very suspicious when an audio player requires its own driver for its work
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So when developers update their players, they usually fix bugs, add user ergonomics features, add tag metadata support for new audio formats and codecs. All this does not affect the quality of the audio signal at all. If the sound engine (built on the API provided by the OS) is working properly, there is no need to update the software player anymore.
In my opinion, the main reason why updates are still around is because the developers want to add new usability features or fix some bugs in the ones that were added before.