Tar might've been designed for use with tape, but no part of its design makes the HDD/SSD use-case worse just to work better with tape.
But that "something better" isn't zip. It's probably something that doesn't currently exist.
https://www.sqlite.org/sqlar.html / https://news.ycombinator.com/item?id=28668615
That makes it unsuitable as a tar replacement for many use cases.
I use tar.gz as my go-to archive format, don't get me wrong. It's easy, well-supported, handles POSIX concepts well, and is pretty universal. But seekability isn't it's strong-suit.
In a .zip, the files are each compressed individually using DEFLATE and then concatenated to create an archive, whereas in a .tar.gz the files are first concatenated into a .tar archive and then DEFLATEd all together.
Because of this, a .tar.gz often achieves much better compression on archives containing many small files, because the compression algorithm can eliminate redundancies across files. The downside is that you can’t decompress an individual file without decompressing every preceding file in the stream, because DEFLATE does not support random access. (And so tar’s lack of index is an advantage here; an index would not be useful if you can’t seek.)
This is why e.g. open source software downloads often use .tar.gz. A source code archive has hundreds or thousands of tiny text files with a ton of redundancy between files in variable & function names, keywords, common code snippets/patterns, etc., so tar.gz delivers significantly better compression than zip. And there’s little use for random access of individual files, since all the files need to be extracted in order to compile the program anyway.
The abbreviation “tape archive” may be anachronistic nowadays, but the performance cbaracteristics of a tape drive — namely, fast sequential access but absolutely awful random access — coincide with the performance characteristics of compression algorithms. So an archive format designed for packaging files up to be stored on a tape is perfect for packaging files up to be compressed.
I don't even know if it's true that tar is less common than zip. I know zip is incredibly common, but truly, so is tar. In the UNIX world, _everything_ happens through tar. And as someone who almost exclusively operates in the UNIX world, I interact with zip files very rarely, while I work with tarballs all the time.
Just don't blame the format for a deficiency in your operating system, that's all I'm saying.
Should windows have native support for tar.gz files? Maybe! Maybe not. I dunno. So when I come across something using that format for windows what it really comes across is half-ass Windows support. Which isn’t the end of the world. But it’s rarely a good sign.
Also on a fresh install I install WSL, so tar is always available that way too.
That's not to say tar is wrong to not have native compression, it's just one reason why it's not crazy for archive formats to natively support compression.
zip files are an ancient format, not without flaws too.