When I point an (un)packing program at a packed archive, the default action should be to fucking unpack it.
And when I point it at anything else, it should pack it into the default format.
The problem is, tar isn't a packing program, it's a tape archive program that's been repurposed for general files-to-file archival with optional compression plugins
At this point, if it were written today, it probably would behave as you suggest, but changing it now would break too many things that use it
Then it would've been time to deprecate it for this purpose, and use something sensible instead, say about 13 years ago.
All the old stuff can then keep using tar, but the nicer option can become the standard for user-friendly file extraction.
"long-standing conventions" is how you end up with Internet Explorer still pre-installed on Windows Server 2025.
And when was the last time you used the tar "tape archiver" to archive things on tape?
$ tar -h; echo $?
tar: You must specify one of the '-Acdtrux', '--delete' or '--test-label' options
Try 'tar --help' or 'tar --usage' for more information.
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